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Birds learn to avoid plants that host dangerous insects: study

by University of Bristol

Birds learn to avoid plants that host dangerous insects, researchers have found
Cinnabar larvae feeding on ragwort. Credit: Callum McLellan

Young birds that eat insects with conspicuous warning colouration to advertise their toxicity to would-be predators quickly learn to avoid other prey that carry the same markings. Developing on this understanding, a University of Bristol team have shown for the very first time that birds don’t just learn the colors of dangerous prey, they can also learn the appearance of the plants such insects live on.

To do this, the scientists exposed artificial cinnabar caterpillars, characterized by bright yellow and black stripes, and non-signaling fake caterpillar targets to wild avian predation by presenting them on ragwort and a non-toxic plant—bramble, which is not a natural host of the cinnabar. Both target types survived better on ragwort compared to bramble when experienced predators were abundant in the population.

They were also interested in whether birds use the bright yellow flowers of ragwort as a cue for avoidance. They tested this by removing spikes of flowers from the ragwort and pinning them onto bramble, then recording target survival on either plant. In this second experiment, only the non-signaling targets survived better on plants with ragwort flowers, compared to the same plant type without the flowers. The survival of the cinnabar-like target was equal across all plant treatments

Lead author Callum McLellan, a graduate student at the School of Biological Sciences, said “Cinnabar caterpillars have this really recognizable, stripey yellow and black appearance. They also only live and feed on ragwort, which itself has distinctive yellow flowers. We have shown that birds learn that the ragwort flowers are a cue for danger, so can avoid going anywhere near toxic prey. It’s more efficient to avoid the whole plant than make decisions about individual caterpillars.”

Birds learn to avoid plants that host dangerous insects, researchers have found
Ragwort. Credit: Callum McLellan

Co-author Prof Nick Scott-Samuel of the School of Psychological Science, said “Our findings suggest that insect herbivores that specialize on easily recognizable host plants gain enhanced protection from predation, independent of their warning signal alone.”

Prof Innes Cuthill, who conceived the study, added “Interestingly, any camouflaged caterpillars living on the same plant also benefit from birds‘ learnt wariness of ragwort, despite being perfectly good to eat.

Birds learn to avoid plants that host dangerous insects, researchers have found
An adult cinnabar moth on a ragwort stem. Credit: Callum McLellan

“Our results provide the opening to a brand-new discussion on how toxicity initially evolved in insect prey, and the conditions under which warning colouration is, or is not, favored.”

The study “Birds learn to avoid aposematic prey by using the appearance of host plants” is published in Current Biology .


Explore furtherEvolutionary change in protective plant odors help flora evade invasive species over time


More information: Birds learn to avoid aposematic prey by using the appearance of host plants, Current Biology (2021).Journal information:Current BiologyProvided by University of Bristol

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“Insect Apocalypse” – Study Reveals Drastic Decline of Aquatic Insect Population in Paraná River Basin

TOPICS:Agência FAPESPEcologyEntomologyInsect

By FAPESP SEPTEMBER 30, 2021

Analysis of data collected over 20 years suggests the decline is due to the construction of over 180 dams (dragonfly emerging from aquatic naiad state). Credit: Alexandre Castagna/Wikimedia Commons

Analysis of data collected over 20 years suggests the decline is due to the construction of over 180 dams on the Paraná basin and its tributaries.

Research conducted in Brazil for more than 20 years in the Paraná River basin shows a drastic fall in the number of aquatic insects in the region, which is considered well-preserved and distant from the negative impacts of agriculture, cattle breeding, and urbanization.

The fieldwork was done by researchers affiliated with the State University of Maringá’s Center for Research in Limnology, Ichthyology and Aquaculture (NUPELIA-UEM). The data was systematized by Gustavo Romero, a professor at the University of Campinas’s Institute of Biology (IB-UNICAMP). An article on the study is published in a special issue on insect decline of Biology Letters, a journal of the UK’s Royal Society.

“Our study analyzed data collected on a seasonal basis over a 20-year period. We detected a decline from thousands to tens of individuals per square meter,” Romero told Agência FAPESP.

A commentary on the study by one member of the team is published in The Conversation.  

The drastic decline in insect populations is a global phenomenon, Romero said, and studies have shown its correlation with human activities. A meta-analysis published in Science pointed to a fall in the number of terrestrial insects but claimed to have detected a rise in the abundance of aquatic insects. This article has since been contested by critics who argue that its authors based their conclusions on too small a sample, with only 7% of the insect datasets in their analysis coming from the tropics and the rest almost exclusively from the United States and Europe.

Romero et al. studied a floodplain with an area of 40 square kilometers containing rivers, shallow lakes, channels and backwaters. The main cause of the decline in insect populations there was the construction of over 180 dams along the Paraná and its tributaries, which form one of South America’s largest freshwater systems, draining much of the central and southern portion of the continent.

The study was supported by FAPESP via two grants awarded to Romero, and a postdoctoral fellowship awarded to Pablo Antiqueira, also a co-author of the published article. The study was conducted under the aegis of the FAPESP Research Program on Biodiversity Characterization, Conservation, Restoration and Sustainable Use (BIOTA-FAPESP) and the FAPESP Research Program on Global Climate Change (RPGCC). 

“A sharp decline was observed not only in more susceptible species but in all aquatic insect orders and families that live in the area. These insects inhabit freshwater environments until they reach adulthood when they migrate to terrestrial environments. This includes dragonflies and water beetles, to mention only the most well-known,” Romero said.

Because some insects transmit diseases (e.g. Aedes aegypti, which transmits dengue, zika, and yellow fever), many people wrongly think all insects are harmful to humans. “The insects that are being decimated in the Paraná River basin are extremely useful. They provide many ecosystem services, including pollination, biological control of crop pests and disease-transmitting insects, decomposition of organic matter, and nutrient cycling,” Romero said. 

Consequence of dams

Dams have impacts of three kinds, Romero continued. First, they make the water much clearer because particles in suspension settle on the reservoir bed before the flow enters the spillway. Deprived of their murky water camouflage, the insects that live downstream of the dam are even more vulnerable to being eaten by fish.

Second, the exotic fish species introduced into dam reservoirs to promote sport fishing, such as the peacock bass (tucunaré) brought from the Amazon, are omnivores and eat insects as well as native fish.

The third type of impact detected was a chemical imbalance of the nutrients in the water, changing the proportions of nitrogen and phosphorus. “The algae that proliferate in dam reservoirs fix nitrogen from the atmosphere and transfer it to the water. Part of the phosphorus is deposited on the reservoir bed. The water that flows through the dam spillway is poor in phosphorus and proportionally richer in nitrogen as a result. This changes its nutritional quality, affecting the animals that depend on a balanced quantity of these nutrients,” Romero explained.

The Paraná River basin touches seven Brazilian states. Technically it is a sub-basin and, alongside the Paraguay and Uruguay River sub-basins, part of the Plata River system, one of South America’s three main basins. The other two are the Amazon and São Francisco River basins. Changes occurring in the ecosystems of the Paraná River sub-basin are therefore highly significant for the continent as a whole, and the decline in aquatic insect populations shows how human activities affect it even without taking into account the use of pesticides and sewage disposal into its rivers and lakes.

The world has some 5.5 million insect species, 80% of which have yet to be described by science. This huge animal population, the most numerous on the planet, is rapidly being reduced by human activities, characterizing what some researchers are already calling the “insect apocalypse.”

Reference: “Pervasive decline of subtropical aquatic insects over 20 years driven by water transparency, non-native fish and stoichiometric imbalance” by Gustavo Q. Romero, Dieison A. Moi, Liam N. Nash, Pablo A. P. Antiqueira, Roger P. Mormul and Pavel Kratina, 9 June 2021, Biology Letters.
DOI: 10.1098/rsbl.2021.0137

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SEPTEMBER 29, 2021

Bacteria stunt with established plant-soil feedback theory

by Leiden University

Bacteria stunt with established plant-soil feedback theory
Credit: Leiden University

“What I find most alluring about soil life is that you can steer it,” researcher Martijn Bezemer of the Institute Biology Leiden (IBL) reveals. “You can ask: What do you want? And then I can transform the soil into something you need. At least, that is what we thought.”

For years, Bezemer studied the interaction between plants and the soil microbiome: The bacteria and fungi living in the soil. “This microbiome and the plants affect each other, by the chemicals they release, for instance. We call that plant-soil feedback,” the researcher explains.

It works as follows: when plant A is put in the soil, its surrounding soil changes. “In this way, you create a soil typical for plant A, thus soil A, with a matching microbiome,” Bezemer says. But when plant A is replaced by plant B, the microbiome in the soil will slowly change into that belonging to plant B. “You can keep changing the soil, even with plant C, D or E. In this way, you could create desired microbiomes so that e.g. certain crops that you then plant in the soil can grow even better.”

“However, it is remarkable that even though researchers are very fond of studying these plant-soil feedbacks and in steering soils, but that this has not yet been tested empirically so far. Therefore, in fact, it is just an assumption,” Bezemer states. “In this latest study, we did test this theory.” For a year, he and his team, a collaboration between the IBL and the Netherlands Institute of Ecology (NIOO-KNAW), grew six grassland species outdoors in large containers and regularly tested the microbiome’s composition in the soil for each of those species.

Sensitive bacteria

After a period of three to four months of plant growth, the fungi in the soil reach an established composition. This was in line with the plant-soil feedback theory. Yet, even after a year, this was not the case for the bacteria in the soil.

Bezemer: “If you would measure today, you would see different bacteria in the soil than a few weeks earlier. That was quite the surprise.” Still, there is an explanation for this result. “Bacteria are very sensitive to factors like moisture and temperature, after all.”

From soil A to B?

In the second part of the study, the team went a step further. “This was the real feedback phase. Each of the large containers, where until then only plants of one species was grown, was divided into six parts. As an example, in a container with plant A and soil A, we now wanted to test the effect of regrowing plant A, ánd the effect of planting B to F on soil A,” the researcher explains.

That was an enormous task. “Make no mistake, as we had five containers for each plant species to start. So with six plant species, we had thirty measuring points for a year already. Now, we multiplied that with six: 180 points, tested for six months by a team of seven people to look at which DNA we could find. And thereafter, Emilia Hannula, the first author of the article, got to analyze this enormous database.”

Hannula adds: “You rarely get the chance to study soil microbes in this amount of detail to detect patterns and answer important questions,” she says. “There are global studies out there with less data than we analyzed here for one soil, only changing the combination of plants growing now and earlier in it.”

The setup should answer two questions. Will the soil change with the presence of the new plants? And will the effect of the previous plant, the so-called soil legacy, still be visible? After six months, legacies of the first plant were still visible, but only for fungi. However, the footprint of the new plant on the soil fungi had also already well established. None of this was the case for bacteria and it appeared that bacteria in the soil are largely irresponsive to the plants that grow in the soil.

Twist in the roots

However, there is a twist in this story. “We also looked at the microbiome in the roots of all plants grown in all the different soils. We call these microbes inside the plant endophytes,” Bezemer says. “It turned out that even though bacteria belonging to the first plant were long gone in the soil, they still could be detected in the roots of the second plant! In the root of plant B, we found bacteria of soil A. Well, that ís interesting,” he stated enthusiastically.

These endophytes can greatly influence plant growth, and this means that a plant can have a long-lasting effect on another later growing plant even when the legacy of the first plant in the soil has already faded away.

Bezemer suspects that the bacteria and fungi, right after planting the second plant species in the soil, have entered the roots through small cuts caused by planting. In the root, there is a safer and more constant environment, in which both fungi and bacteria can endure and these endophytes remained present inside the plants. To the surprise of the researcher. “The bacterial soil legacy of the first plant is preserved, albeit in the roots of the second plant and not in the soil. That is something we had never thought of before. They are still there!”


Explore furtherPredicting plant-soil feedbacks from plant traits


More information: S. Emilia Hannula et al, Persistence of plant-mediated microbial soil legacy effects in soil and inside roots, Nature Communications (2021). DOI: 10.1038/s41467-021-25971-zJournal information:Nature CommunicationsProvided by Leiden University

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Aquatic insects are sensitive to light pollution

by Forschungsverbund Berlin e.V. (FVB)

Aquatic insects are sensitive to light pollution
People like to settle near waters—so freshwater systems are strongly affected by light pollution. Credit: Markus Venohr

Light pollution—too much artificial light in the wrong place at the wrong time is one reason for the decline in insect numbers worldwide. New research from the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) shows that current strategies for reducing the impact of light pollution do not go far enough in protecting aquatic insect species.

Most people are familiar with the sight of insects swarming around a streetlight at night. This well-known phenomenon shows one of the most severe ecological effects of artificial light at night—disruption of nocturnal insect location and behavior. Such is the attraction of artificial light to nocturnal insects, that the light acts like a “vaccuum cleaner,” drawing insects away from their regular habitat and out of their usual behavioral cycles. The effect not only disrupts the insects’ behavior and distribution, but has knock-on effects on the ecosystems in which they play a vital part. For example, nocturnal insects play an important role as pollinators. The recent German “Insect Protection Act” (Federal Nature Conservation Act) has anchored the implementation of insect-friendly lighting as a crucial strategy for biodiversity protection.

Insects and larvae are also attracted to light under water

In numerous studies, Dr. Franz Hölker’s team has been able to show the influence of artificial light on flying and ground-dwelling insects. Now the researchers have investigated the effect on aquatic insects and insect larvae. Inland waters are particularly affected by light pollution as the shores of rivers and lakes are often densely built-up and brightly lit at night.

To study the effect, the researchers had to go where it is still really dark at night. In the Westhavelland Star Park near Berlin, they set up underwater traps for insects in water ditches and installed lights at different wavelengths. “In the illuminated water areas we found significantly more insects in the traps than in the unlit ones. This demonstrates that the vacuum cleaner effect of artificial light is felt even under water. Affected insects are impaired in their search for food and mates and become easier prey for predatory species,” Franz Hölker explained the result of the field study.

Land and water insects: Not on the same wavelength

Many flying insects are particularly sensitive to short-wave, blue light and, as such, campaigns to protect insects against light pollution have focussed on reducing blue light wavelengths in streetlamps. However, the researchers found that aquatic insects don’t exhibit this preference, and as such current blue-light mitigation strategies may not be enough. “Most species of aquatic insects seem to be attracted to long-wave light rather than short-wave light,” explained Franz Hölker.

Light conditions in water are not the same as on land. The water body acts like an optical filter, altering the light spectrum and intensity. For example, if there is organic material in the water and it becomes more turbid. Short-wave, blue light in particular is attenuated as the distance from the light source increases.

“For the protection of flying insects, we recommend reducing the blue fraction of the light, but this does not help aquatic insects according to our study. Therefore, it would certainly make sense for lighting at water bodies to focus on alternative conservation measures—for example, to generally avoid direct lighting of water surfaces, and to reduce the intensity and duration of lighting in areas close to water bodies,” Franz Hölker summarized.


Explore furtherWaterside lighting drastically disrupts wildlife in the surrounding ecosystem


More information: Impact of Different Wavelengths of Artificial Light at Night on Phototaxis in Aquatic Insects, Integrative and Comparative Biology, 2021; icab149, doi.org/10.1093/icb/icab149Provided by Forschungsverbund Berlin e.V. (FVB)

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Hoverflies navigate using sun and body clock

Date:September 21, 2021Source: University of Exeter Summary: Hoverflies use a combination of the sun and their body clock to navigate when they fly south for the winter, new research shows.Share:FULL STORY


Hoverflies use a combination of the sun and their body clock to navigate when they fly south for the winter, new research shows.

The insects keep the sun on their left in the morning, then gradually adjust to maintain a southward route as the day goes on.

Pied and yellow-clubbed hoverflies — which are important pollinators — spend their summers in locations such as the UK and Scandinavia, then fly to the Mediterranean and North Africa in autumn.

These migrations are known to happen on sunny days, but the new study — led by the University of Exeter — is the first proof of a “time-compensated sun compass” in hoverflies.

“Simply flying towards the sun would lead them south, but this would create a winding, inefficient route,” said lead author Richard Massy, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“Our study shows that hoverflies account for the sun’s movement using their circadian rhythm.

“Other animals, including certain birds and butterflies, are known to have this ability. Our work suggests that it has independently evolved across multiple insects.”

Researchers caught migrating hoverflies at a mountain pass in the Pyrenees.

The insects were placed in a “flight simulator,” which held them in place but allowed them to swivel freely.

The hoverflies could see the sun but not the ground (meaning they could not navigate using landmarks) and the results showed they headed south by adjusting their course based on the sun’s position and the time of day.

This was further tested by placing some hoverflies in an artificial lighting environment for several days to shift their body clocks, then testing their navigation.

With their circadian rhythm disrupted, their direction of flight shifted westward — supporting the conclusion that they navigate using a time-compensated sun compass.

Dr Karl Wotton, of the University of Exeter, said: “Understanding how these insects navigate can help us predict their movements.

“This could be useful for conservation measures, such as limiting the use of pesticides at key migration times.

“Hoverflies are also important predators of crop pests such as aphids, so understanding their migrations could help us use them as natural pest controllers.”

The research team included the University of Bristol, and funding came from the Royal Society and the Natural Environment Research Council’s GW4 Doctoral Training Programme.


Story Source:

Materials provided by University of ExeterNote: Content may be edited for style and length.


Journal Reference:

  1. Richard Massy, Will L. S. Hawkes, Toby Doyle, Jolyon Troscianko, Myles H. M. Menz, Nicholas W. Roberts, Jason W. Chapman, Karl R. Wotton. Hoverflies use a time-compensated sun compass to orientate during autumn migrationProceedings of the Royal Society B: Biological Sciences, 2021; 288 (1959): 20211805 DOI: 10.1098/rspb.2021.1805

Cite This Page:

University of Exeter. “Hoverflies navigate using sun and body clock.” ScienceDaily. ScienceDaily, 21 September 2021. <www.sciencedaily.com/releases/2021/09/210921195801.htm>.

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Oliva released 10,000 predatory insects of the cotonet in 10 hectares of citrus fruits

The Department of Agriculture of Oliva has carried out a controlled release of the Cryptoleamus montrouzieri predatory insect in 10 hectares of citrus fields in the municipality of Oliva to deal with the cotonet pest that is affecting this municipality.

The Councilor for Agriculture, Miquel Doménech, received 10,000 specimens of Cryptoleamus -a voracious and highly effective predator of different pests- to continue with their biological control project, without using insecticides or toxins. The councilor thanked the different groups and agricultural associations that support the project and announced that there will be future releases.

Source: saforguia.com 

Publication date: Wed 29 Sep 2021

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TAMIL NADU

The Hindu

VIT trains students, farmers to spray bio-pesticide using drones

SPECIAL CORRESPONDENTVELLORE, SEPTEMBER 22, 2021 11:48 ISTUPDATED: SEPTEMBER 22, 2021 11:48 IST

  • The Vellore-based VIT School of Agricultural Innovations and Advanced Learning (VAIAL) provides training for students and farmers to spray biopesticides in farmlands using drones.   | Photo Credit: Special Arrangement

The programme aims to create awareness about the application of drones in organic paddy cultivation among farmers of Vellore.

The VIT School of Agricultural Innovations and Advanced Learning (VAIAL) is training its students as part of a hands-on training programme for final-year pupils, and farmers to spray bio-pesticides in farmlands using drones.

According to a press release, the training programme aims to create awareness about the application of drones in organic paddy cultivation among farmers of Vellore.

A section of farmers in Vellore and final year students of the B.Sc. (Hons.) Agriculture course of VAIAL participated in the field demonstration, conducted in association with Chennai-based Garuda Aerospace Private Limited, on using drones for spraying of bio-pesticides, such as neem-seed kernel extract, for controlling sucking pests (stem borer, gall midge and earhead bug) and storage pests (grain moth, rice weevil and grain borer) in paddy, the release added.

Drones are now becoming a potential tool in providing real-time and high-resolution aerial imageries of agricultural fields with minimal influence on the growing crop. These systems can be used throughout the crop growing season to identify problems in the field precisely and make management decisions.

On the occasion, S. Babu, Dean, VAIAL, explained the application of drones in organic farming, whereas R. Thirumalaikumar, Assistant Professor (Agronomy), VAIAL, spoke about the organic practices in paddy cultivation. Technical booklets published by VAIAL were distributed to farmers during the training programme, the release added.

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Proceedings of the Royal Society B

Maternal care in Mid-Cretaceous lagonomegopid spiders

Xiangbo GuoPaul A. Selden and Dong RenPublished:15 September 2021https://doi.org/10.1098/rspb.2021.1279

Abstract

Maternal care benefits the survival and fitness of offspring, often at a cost to the mother’s future reproduction, and has evolved repeatedly throughout the animal kingdom. In extant spider species, this behaviour is very common and has different levels and diverse forms. However, evidence of maternal care in fossil spiders is quite rare. In this study, we describe four Mid-Cretaceous (approx. 99 Ma) amber specimens from northern Myanmar with an adult female, part of an egg sac and some spiderlings of the extinct family Lagonomegopidae preserved, which suggest that adult lagonomegopid females probably built and then guarded egg sacs in their retreats or nests, and the hatched spiderlings may have stayed together with their mother for some time. The new fossils represent early evidence of maternal care in fossil spiders, and enhance our understanding of the evolution of this behaviour.

1. Introduction

Parental care refers to any investment by the parent that enhances the fitness of their offspring, and often at a cost to the survival and future reproduction of the parent [1,2]. Its evolution represents a breakthrough in the adaptation of animals to their environment and has significant implications for the evolution of sociality [35]. This behaviour has evolved independently numerous times among different animal groups [2] and has been observed in many arthropod groups including spiders. Fossil evidence of arthropod parental care has been reported in crustaceans [6,7], insects [810], whipspiders [11] and some early arthropods [1214].

Spiders have a long geological history on Earth, from the Carboniferous period to the present [15,16]. In extant spider species, almost all known cases of parental care are maternal except Manogea porracea, an araneid spider that was reported with amphisexual care [5,17]. Maternal care in spiders is fairly common and has diverse forms [5,18]. However, fossils providing evidence of such behaviour are relatively rare. A number of fossil egg sacs have been found in Cenozoic (65.5 Ma to present) amber, including a sac carried in the chelicerae by a female synotaxid spider [19,20]. They represent the evidence of maternal care in Cenozoic fossil spiders. In addition, the earliest fossil records of spider egg sacs were reported from Mid-Cretaceous Burmese amber, but most of them are doubtful due to the lack of detailed description and photographs [2123]. The early evolution of maternal care in spiders remains poorly known. Here, we describe an adult female, part of an egg sac and some spiderlings of Lagonomegopidae preserved in four pieces of Mid-Cretaceous (approx. 99 Ma) Burmese amber. The new fossils provide early evidence of maternal care in fossil spiders.

2. Material and methods

The amber specimens investigated in this paper are from Tanai Village in the Hukawng Valley, Myitkyina District of Kachin State, Myanmar. The amber-bearing deposits have been dated to the earliest Cenomanian, ca 98.8 ± 0.6 Ma, based on U–Pb radiometric dating of zircons from the volcaniclastic matrix [24]. All specimens are housed at the fossil collection of the Key Laboratory of Insect Evolution and Environmental Changes, at the College of Life Sciences, Capital Normal University, (CNUB; Dong Ren, curator), in Beijing, China.

Preparation and imaging methods follow Selden & Penney [25]. The photographs were taken with a Nikon SMZ 25 and an attached Nikon DS-Ri 2 digital camera system, as well as a Nikon ECLIPSE Ni and an attached Nikon DS-Ri 2 digital camera system. Micro-CT scanning of CNU009432 was carried out with a Micro-CT (MicroXCT-400, ZEISS), located at the Institute of Zoology, Chinese Academy of Sciences. The three-dimensional structure of CNU-ARA-MA2016101 and the egg sac was reconstructed using Avizo software. The line drawings were prepared with Adobe Illustrator CC and Adobe Photoshop CC, the images were processed by Adobe Photoshop CC.

3. Results

In this paper, four pieces of Burmese amber (CNU009371, CNU009431, CNU009432 and CNU009476) were studied. CNU009432 has a large spider (CNU-ARA-MA2016101) and part of an egg sac preserved (figure 1; electronic supplementary material, figure S1). The large spider is covered with emulsion-liked impurities, the dorsal parts of cephalothorax and abdomen are somewhat broken, and some of the leg podomeres are missing. Its large size, peg teeth on the promargin of the chelicera, unmodified pedipalps, spineless legs and trichobothria on the leg tarsus indicate that it belongs to Lagonomegopidae, and is an adult female [26]. Detailed description and measurements of CNU-ARA-MA2016101 can be found in electronic supplementary material, S1. The egg sac is broken and located under the female spider. From the cross section, dozens of prelarvae and their egg membranes wrapped in the silk of the egg sac can be clearly observed (figure 1e,gi). The diameter of the silk threads is about 1 µm.

Figure 1.
Figure 1. Photographs and drawings of a lagonomegopid spider (CNU-ARA-MA2016101) and egg sac in Burmese amber CNU009432. (a) Habitus, dorsal view; (b) three-dimensional CT reconstruction, dorsal view, grey represents CNU-ARA-MA2016101, yellow represents egg sac; (c) schematic drawing of dorsal habitus; (d) habitus, ventral view; (e) cross-section of egg sac, the details in boxes are enlarged and shown in other figures; (f) three-dimensional CT reconstruction of egg sac, dorsal view; (g) silk thread of the spider egg sac; (h) details of egg sac, showing prelarvae and egg membranes (arrow); (i) details of egg sac, showing prelarvae and egg membranes (arrows); (j) left tarsus I lateral view, showing trichobothria (asterisks). Scale bars represent 2 mm (a,c,d), 0.5 mm (e), 0.2 mm (h,i,j) and 0.01 mm (g); scale bars are absent in (b) and (f). (Online version in colour.)

CNU009476 has 24 spiderlings preserved, and is convex on one side and flat on the other in lateral view (figure 2; electronic supplementary material, figure S2). Most of the spiderlings are somewhat deformed and broken due to the effect of taphonomy; only semitransparent cuticles with setae and bristles remain. In addition, spider silk threads, some pieces of arthropod cuticular fragments, several dipterous insects and parts of two large arthropod legs are preserved as syninclusions. The diameter of the silk threads is about 1 µm; they clump together loosely in a mass and entwine various pieces of detritus including wood fibres, arthropod cuticular fragments and some unidentifiable inclusions (figure 2f–i). CNU009431 has 26 spiderlings that are deformed due to the effect of taphonomy, and part of a large arthropod leg preserved; a cockroach is present as a syninclusion (figure 3ac; electronic supplementary material, figure S3). In CNU009371, a total of 34 spiderlings are preserved, most of them strongly taphonomically deformed (figure 3df; electronic supplementary material, figure S4). In addition, a wasp is present in CNU009371 as a syninclusion.

Figure 2.
Figure 2. Photographs of inclusions in Burmese amber CNU009476. (a) Photograph of CNU009476, convex side view, the details in boxes are enlarged and shown in other figures; (b) photograph of CNU009476, flat side view, the details in boxes are enlarged and shown in other figures; (c) photograph of CNU009476, lateral view, showing the convex side and flat side; (d) a dipterous insect and several pieces of arthropod cuticular fragments; (e) overall habitus of CNU-ARA-MA2016123, dorsal view, showing the large PME situated on anterolateral corner of carapace (arrows); (f) spider silk threads and inclusions entwined by them, showing wood fibres (arrow); (g) inclusions entwined by spider silk, showing wood fibres (arrow), the details in box are enlarged and shown in other figure; (h) details of spider silk thread; (i) a piece of arthropod cuticular fragment. Scale bars represent 2 mm (a,b,c), 0.5 mm (d,e), 0.2 mm (f,g) and 0.025 mm (h,i). PME, posterior median eye(s). (Online version in colour.)
Figure 3.
Figure 3. Photographs of inclusions in Burmese amber CNU009431 and CNU009371. (a) Photographs of CNU009431, overall photograph of amber on the bottom left, the details in boxes are enlarged and shown in other figures; (b) overall habitus of CNU-ARA-MA2016135, dorsal view, showing the large PME situated on anterolateral corner of carapace (arrows); (c) overall habitus of CNU-ARA-MA2016139, dorsal view; (d) photographs of CNU009371, overall photograph of amber on the top left, the details in boxes are enlarged and shown in other figures; (e) overall habitus of CNU-ARA-MA2016182, dorsal view, showing the large PME situated on anterolateral corner of carapace (arrows); (f) overall habitus of CNU-ARA-MA2016163, ventral view, showing the large PME situated on anterolateral corner of carapace (arrow). Scale bars represent 2 mm (a,d), 0.5 mm (e,f) and 0.2 mm (b,c). PME, posterior median eye(s). (Online version in colour.)

We consider that all spiderlings in the same piece of amber (CNU009371, CNU009431 and CNU009476) are siblings of the same instar because of their similar sizes and morphological characters. Their small sizes and immature morphological characters show that they were trapped by resin not long after hatching. Although most of the spiderlings are not well preserved, they can be identified as members of Lagonomegopidae by their two large eyes positioned on the anterolateral flanks of the carapace, peg teeth on the promargin of the chelicera, spineless legs and the presence of trichobothria on the leg tarsus. Detailed description and measurements of the lagonomegopid spiderlings in CNU009476 can be found in electronic supplementary material, data S2 (electronic supplementary material, figure S5).

In CNU009476, there are two parts of arthropod legs that have quite different characters preserved. One of them (figure 2a,b: arthropod leg A) has several macrosetae on the surface of the podomeres, while the other (figure 2a,b: arthropod leg B) is spineless and has a kind of special lanceolate seta. Interestingly, such lanceolate setae can be observed on the part of the spineless arthropod leg preserved in CNU009431 (figure 3a: arthropod leg C), the leg of the large lagonomegopid spider preserved in CNU009432 and the type specimen of Odontomegops titan Guo et al. [26], which belongs to Lagonomegopidae as well (electronic supplementary material, figure S6).

4. Discussion

(a) Maternal care in lagonomegopids

In extant spider species, the strategies of maternal care have different levels and diverse forms in different spider groups, ranging from laying the eggs in a sheltered place to feeding the young [5,18]. Spider eggs are always protected by silk, from a few silk threads wrapping around the eggs to having multiple inner layers of silk and a tough cocoon wall [18]. The spider egg sac is so common that its construction was not treated as maternal care in some previous studies [27]. In this study, we consider it as a form of maternal care, under the definition proposed by Trivers [1] and Royle et al. [2]; thus, all spiders show a degree of maternal care [5]. The egg sac serves as a barrier against the entrance of parasites and predators [2831]. The egg sac preserved in CNU009432 is composed of a loose mesh of threads and without special decorations, it represents an undoubted fossil record of a spider egg sac from Cretaceous amber.

In addition to protecting the eggs by building an egg sac, many modern spiders actively guard or carry their egg sacs. Spider egg sacs may be attached to the substrate and actively guarded by the adult female; others carry the egg sacs in their chelicerae (e.g. pholcids, scytodids, pisaurids), in their legs (e.g. huntsman spiders) or attached to the spinnerets (e.g. lycosids) until the young hatch (electronic supplementary material, figure S7). In CNU009432, the egg sac is preserved closely beneath the large spider. The eggs have developed into prelarvae, and some of them have shed their egg membranes (figure 1e,hi). The prelarvae do not show enough characters that can be used to identify them to Lagonomegopidae or any other certain spider family. Nevertheless, the most reasonable interpretation of this piece of amber is still that the mother lagonomegopid spider was guarding her egg sac when trapped by resin. The maternal behaviour of egg guarding occurs in many spider families [5]. It plays an important role in protecting against egg predators [32,33] and regulating the temperature of egg sacs [34,35], thus benefitting the survival and successful hatching of eggs [5].

In CNU009476 and CNU009431, the spineless arthropod leg B and arthropod leg C have a kind of lanceolate seta which is also present in some lagonomegopid spiders, and the presence of spineless legs is a diagnostic feature of Lagonomegopidae. It hints that arthropod leg B and arthropod leg C possibly belong to two large lagonomegopid spiders, maybe the mothers of the spiderlings. In addition, unlike the silk of the egg sac in CNU009432, the loose silk threads in CNU009476 entwine various pieces of detritus, and are, therefore, probably part of a retreat or nest where the mother spider guarded her egg sac. This implies that the hatched lagonomegopid spiderlings may stay together with their mother in the retreat or nest for some time, rather than dispersing immediately.

In some living species, the mother spider provides food for the spiderlings by sharing prey [36], regurgitation [37], secreting nutritive liquid [38], trophic eggs [39] or matriphagy [5,18,40]. Although some pieces of arthropod cuticular fragments and several dipterous insects are preserved as syninclusions in CNU009476, there is no evidence indicating that offspring feeding behaviour existed or not in Lagonomegopidae. With the aforementioned evidence and discussions, we conclude that adult lagonomegopid females probably built and then guarded egg sacs in their retreats or nests, and the hatched spiderlings may stay together with their mother for some time (figure 4). It is worth mentioning that mother spiders with offspring fossilized in amber represent a moment in time, and the discoveries of more similar fossils, especially if the offspring are in different instars, will add material for further study of maternal care and even potential social behaviour in spiders.

Figure 4.
Figure 4. Ecological reconstruction of a female lagonomegopid spider guarding her egg sac. Painted by Xiaoran Zuo. (Online version in colour.)

(b) Evolution of maternal care in spiders

Egg-sac building probably evolved with the origin of spiders. Egg guarding behaviour is relatively common in the major lineages of arachnids. Also, females of Amblypygi, Schizomida and Uropygi, which are suggested as the closest extant relatives of spiders in previous phylogenetic analyses [4143], carry their eggs glued to their ventral abdomens until the young emerge, then carry the first instar offspring on their backs. Spiders probably evolved from egg guarding ancestors. The ability to produce silk is generally considered a defining feature of spiders [44,45]. One hypothesis for the origin of silk production in spiders is that silk evolved from proteinaceous secretions involved in construction of the egg sac in spider ancestors [46]. In other words, the original function of spider silk may have been to protect the eggs. Liphistiids, the sister group to all other extant spider species, show some features that seem to be primitive for spiders [47]. They build globe-shaped egg sacs at the bottom of their burrows using silk and soil [48,49], but it is still unclear whether other maternal behaviours exist in this ‘living fossil’ family. CNU009432 shows the morphology of a spider egg sac and the putative egg-guarding behaviour from the Mid-Cretaceous, the fossil egg sac is similar to modern ones. Egg-sac building and guarding are probably conservative and successful strategies of maternal care in spiders.

More complex maternal care (offspring guarding and feeding) may have evolved independently multiple times across highly divergent spider lineages [5,50]. Even among closely related spider groups, the forms of maternal behaviour may be very different. For example, the egg sac of pirate spiders (Mimetidae) is usually laid on vegetation, then abandoned by the mother [47]. However, females of Anansi insidiator are known to carry the eggs and spiderlings with their chelicerae, and some species of Mimetus build nursery webs for the offspring [51]. Furthermore, some species of Theridiidae, which belongs to the same superfamily as Mimetidae [52,53], have a subsocial or even social life history [5,18].

Lagonomegopidae is an extinct spider family which was widespread in the Northern Hemisphere but only reported in the Cretaceous period [26,54]. A recent study suggested that it is the potential sister group to extant Palpimanoidea [55]. Our new fossils show that lagonomegopid females built an egg sac and may have guarded it, even possibly staying together with the hatched spiderlings for some time. In the five families of extant palpimanoid spiders, some archaeid and mecysmaucheniid females were observed and reported guarding their egg sacs [47,56,57], while maternal care in the other three palpimanoid families (Palpimanidae, Huttoniidae and Stenochilidae) is still unknown.

The evolution of maternal care is helpful for spiders in response to environmental pressures and represents an important step in the evolution of spider society [2,5]. The new fossils provide early evidence of maternal care (egg-sac building and guarding, and perhaps even offspring guarding) in fossil spiders, and enhance our understanding of the evolution of this behaviour.

Ethics

In this study, we reported 85 lagonomegopid specimens (CNU-ARA-MA2016101–2016185) preserved in four pieces of Burmese amber: CNU009371, CNU009431, CNU009432 and CNU009476. They are permanently housed in the Key Laboratory of Insect Evolution and Environmental Changes, College of Life Sciences and Academy for Multidisciplinary Studies, Capital Normal University, Beijing, China (CNUB; Dong Ren, Curator). All these amber specimens were collected from Kachin (Hukawng Valley) of northern Myanmar, and were dated at 98.79 ± 0.62 Ma based on U–Pb dating of zircons. They were acquired by Mr Fangyuan Xia before 2013 and donated for this study in 2015.

Data accessibility

The data supporting the conclusions of this article consist of (i) figures 13 and descriptions of the ambers included within the article; (ii) electronic supplementary material, figures S1–S7 and detailed descriptions of the lagonomegopid female and spiderlings which are provided in the electronic supplementary material; and (iii) the raw Micro-CT data and three-dimensional CT reconstruction of CNU009432, which are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.7m0cfxpv0 [58].

Supplementary information are provided in electronic supplementary material [59].

Authors’ contributions

X.G.: Software, validation, visualization, writing-original draft; P.A.S.: supervision, validation, writing—original draft, writing—review and editing; D.R.: project administration, supervision, validation, writing—original draft, writing—review and editing.

All authors gave final approval for publication and agreed to be held accountable for the work performed therein.

Competing interests

We declare we have no competing interests.

Funding

This research is supported by grants from the National Natural Science Foundation of China (grant nos. 31730087 and 32020103006).

Acknowledgements

We thank Taiping Gao, Yongjie Wang, Lifang Xiao and Haoqiang Zhang of Capital Normal University for their helpful comments on this study. We are grateful to Caixia Gao (Institute of Zoology, Chinese Academy of Sciences) for providing help in reconstructing the three-dimensional structure of CNU-ARA-MA2016101. We thank Xiaoran Zuo for providing the ecological reconstruction picture. We thank Fangyuan Xia for donating specimens for this study. We thank the Editorial Board of Proceedings B, and in particular, Dr John Hutchinson. We express our gratitude to three anonymous reviewers for their valuable comments and suggestions.

Footnotes

Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare.c.5604578.© 2021 The Authors.

Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.Previous Article

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Hans News Service

Amalapuram: Coconut growers fear spread of Black Scorch disease to plantation Hans News Service   |  2 Sep 2021 1:23 AM IST

Coconut growers fear spread of Black Scorch disease to plantation  In Konaseema region, coconut plantation in 15 acres, around 880 trees affected and due to Black Scorch disease The Chief Minister instructs the officials to form a scientific committee to investigate the issue Amalapuram: ‘Kerala’ of Andhra Pradesh, as Konaseema is known for its abundant coconut plantation in the region, grip of fear as the money fetching coconut trees are adversely affected by a strange and peculiar disease called ‘Black Scorch’ disease in Nellivaripeta, Billakuduru village, Kothapeta mandal of East Godavari district Around 880 coconut trees were destroyed in 15 acres due to the disease. Worried of the spread of disease to other trees, many coconut farmers requested the scientists concerned to find a solution to eradicate the disease.

The people of this region solely dependent on the sale of coconuts livelihood and coconuts are exported to various places in the state as well as other states. The farmers allege that the salt water released by the borewells which were dug by ONGC lead to the cause of the disease to the plantation. The experts from YSR Horticulture University visited the area and studied about the nature and cause of the disease. With their expertise they could successfully prevent the spread of the disease to the surrounding trees.

The experts also conducted the water analysis and soil tests, but they couldn’t exactly diagnose the nature of the disease. The MLAs of Konaseema and officials brought the issue to the notice of the Chief Minister YS Jagan Mohan Reddy. The Chief Minister instructed the officials to appoint an expert committee to find cause of the disease and sort out the issue. The farmers appealed the Chief Minister not only curb the spread of the disease including the steps to root out its horizon, but to come to their rescue.

Horticulture officer PBS Amarnath told “The Hans India” that The coconut trees in Konaseema area attracted Black scorch disease in Nellivaripeta, Billakuduru village, Kothapeta mandal of East Godavari district and 880 coconut trees in 15 acres were already died due to the disease. He said that they spent nearly Rs 80,000 to 1 lakh to conduct the tests. He advised the government to invest few lakhs to conducts these types of tests in the future. He added that they could not conduct certain other tests due to lack of funds.

https://www.thehansindia.com/andhra-pradesh/amalapuram-coconut-growers-fear-spread-of-black-scorch-disease-to-plantation-704598

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SpaceX launches ants

SpaceX launches ants, avocados, and robot to space station

A SpaceX shipment of ants, avocados and a human-sized robotic arm rocketed toward the International Space Station on Sunday. The delivery, due to arrive Monday, is the company’s 23rd for NASA in just under a decade.

A recycled Falcon rocket blasted into the predawn sky from NASA’s Kennedy Space Center. After hoisting the Dragon capsule, the first-stage booster landed upright on SpaceX’s newest ocean platform, named A Shortfall of Gravitas.

SpaceX founder Elon Musk continued his tradition of naming the booster-recovery vessels in tribute to the late science fiction writer Iain Banks and his Culture series. The Dragon is carrying more than 2,170 kilograms of supplies and experiments, and fresh food, including avocados, lemons and even ice cream for the space station’s seven astronauts.

The Girl Scouts are sending up ants, brine shrimp and plants as test subjects, while University of Wisconsin-Madison scientists are flying up seeds from mouse-ear cress, a small flowering weed used in genetic research. Samples of concrete, solar cells and other materials also will be subjected to weightlessness.

A Japanese start-up company’s experimental robotic arm, meanwhile, will attempt to screw items together in its orbital debut and perform other mundane chores normally done by astronauts.

Read the complete article at VOA News

Publication date: Mon 6 Sep 2021

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Turning down some lights or applying filters might benefit nocturnal insects, a study suggests

Science News

orange caterpillar eating a leaf
A pebble prominent moth caterpillar (Notodonta ziczac) munches on a leaf. The species has shrunk in number by 45 percent since the 1970s, and new research shows artificial light may play a small role in the insect’s decline.PATRICK CLEMENT/BUTTERFLY CONSERVATION

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By Jonathan Lambert

AUGUST 31, 2021 AT 8:00 AM

Moths flock to streetlights, bewitched by their luminous brilliance. But bathing in brightness all night seems to have consequences for the grounded forms of these fliers. Illuminated stretches of English roads housed up to 52 percent fewer moth caterpillars than adjacent dark patches, researchers report August 25 in Science Advances. Streetlights could be contributing to declining insect populations in developed areas, the researchers say.

Artificial light is generally not good for nocturnal insects. Recent work hints the glow can mess with mating or disrupt pollination (SN: 5/13/15; SN: 8/2/17). But whether night lights contribute to population decline is understudied, says Douglas Boyes, an entomologist at the UK Centre for Ecology and Hydrology in Wallingford, England. 

Boyes and colleagues compared 27 stretches of road that appeared identical except some parts were lit at night and others remained dark. Instead of looking at moth adults that can fly kilometers during their lives, the researchers counted caterpillars, which traverse just meters. At night, the team knocked dozens of species from roadside hedgerows or swept up larvae from grasses, catching nearly 2,500 caterpillars. 

Hedgerows under bright LED lights contained 52 percent fewer caterpillars than dark sections, while areas under duller sodium lamps housed 41 percent fewer. On grassy sections, LED lights cut the population by 33 percent, while sodium lamps had little effect. LED lamps emit a broader spectrum of light than other lamps, which may explain their heightened influence. Caterpillars were fatter in lit sections, which probably indicates abnormal development, Boyes says, but how exactly LED light harms caterpillars remains unclear.

The United Kingdom’s moth population has shrunk by a third in 50 years, but since less than 3 percent of the country lies under strong illumination from streetlights, habitat loss and climate change are more likely to blame than the lights, Boyes says. Still, the work highlights a relatively easy way to give some insects a break, he says. Just turn down the lights, or place filters on LEDs that narrow the spectra of light they shine down.

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS

D.H. Boyes et al. Street lighting has detrimental impacts on local insect populationsScience Advances. Published online August 25, 2021. doi: 10.1126/sciadv.abi8322.

About Jonathan Lambert

Jonathan Lambert is the staff writer for biological sciences, covering everything from the origin of species to microbial ecology. He has a master’s degree in evolutionary biology from Cornell University.

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