Crickets’ old age, new research


This 2013 video from the USA says about itself:

Giant Swarm of Mormon Crickets | National Geographic

Mormon crickets create a creepy scene and even dangerous driving conditions in the American West from early spring through the summer.

Crickets not only turn out to be the real ‘culprits’ in what the United States Trump administration had called a Cuban communist sonic attack on US diplomats; there are more interesting sides to them.

From the University of Exeter in England:

Wild insects ‘get old’ before they die

January 14, 2019

Short-lived wild insects “get old” — losing some of their physical abilities — before they die, new research shows.

Few studies have examined whether insects such as field crickets — whose adult life lasts a few weeks — experience “ageing” in the sense of physical decline in nature.

Insects are used to study ageing in laboratories, but it wasn’t clear whether they only reach “old age” because they are protected from a harsh natural environment.

“Just like humans, crickets get old”, said lead author Dr Rolando Rodríguez-Muñoz, of the Centre for Ecology and Conservation on the University of Exeter’s Penryn Campus in Cornwall.

“Though we didn’t find evidence of ‘live fast, die young’ in this species, those that put more energy into reproduction early in life showed some signs of faster decline as they aged.”

University of Exeter researchers used a network of more than 130 video cameras to study every hour of the lives of a population of wild crickets in a Spanish meadow.

They monitored reproductive effort, ageing and survival over a ten-year period.

They found no evidence of a “trade-off” between reproductive effort in early life (measured by emergence date, calling, searching and winning fights) and survival.

But the crickets that invested more in reproduction did show signs of “ageing” — chirping less and losing more fights.

“There’s a big question in biology about why we fall apart as we get old”, said Professor Tom Tregenza, also of the University of Exeter.

“In the past, it was thought that there was something inevitable about declining with age.

“But there has been a shift towards believing this is something we have evolved to do.

“Ageing may not be about inevitable decline, but about passing our genes on. In other words, we age because — instead of using our energy to maintain ourselves — we put it into reproduction.

“Selection might favour reproduction — passing on lots of copies of your genes — over simply surviving.”

This research is about the field cricket species Gryllus campestris.

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How stick insects move, new study


This video says about itself:

The delightfully improbable stick insect uses two pairs of legs to walk and the front pair to check out what lies ahead. Find out more in this 2016 episode of ScienceTake.

Read more here.

From the University of Cologne in Germany:

Stick insect study shows the significance of passive muscle force for fast movements

January 9, 2019

Zoologists have gained new insights into the motor function of limbs of different sizes. Long, heavy limbs such as arms or legs differ fundamentally from short, light limbs such as fingers in their ability to execute fast movements. While the central nervous system has to actively control fast movements of large limbs, passive muscle force can suffice for the movement velocity and movement amplitude of small and light limbs. That is the result of a study conducted on the stick insect by the zoologists Ansgar Bueschges, Arndt von Twickel and Christoph Guschlbauer at the University of Cologne in cooperation with the visiting scientist Scott Hooper from Ohio University. The paper has now been published under the title ‘Swing Velocity Profiles of Small Limbs Can Arise from Transient Passive Torques of the Antagonist Muscle Alone’ in Current Biology.

There are different basic speed levels in the course of a movement until the entire motor action has been optimally executed, says Bueschges: ‘If we look at the swinging of our legs when we walk, for example, the swinging phase brings the leg back into the starting position for the next step. With this feedback, the swing speed of the leg decreases towards the end, so that the foot does not touch down as quickly. Without the deceleration, the force generated when touching down would be so strong that it would counteract the next step.’ Our nervous system produces this deceleration in large limbs such as the human leg.

For smaller limbs such as insect bones, however, the authors have shown that the slowing of the leg during rapid movements such as the swinging phase is independent of the central nervous system. Von Twickel explains that this is due to the intrinsic muscle characteristics of the limb: ‘If the extensor muscle of a leg joint is actively shortened to produce rapid movements, the inactive flexor muscle is necessarily lengthened. During this stretching, the flexor muscle develops a previously unknown dynamic passive force, which is so large that it can continuously slow down movements to the functionally necessary level.’

In the study, the authors exposed the flexor muscle of the stick insect leg to various stretching scenarios and measured the dynamic forces exerted by the passive muscle against the different stretches. Then, they used the results to dynamically simulate the functioning of a leg joint. The passive dynamic forces of the flexor generated by extensor activation were able to generate a movement that corresponded to the speed profile of an animal.

These results are quite surprising and contradict widespread notions of how small limbs execute fast movements. Bueschges concludes: ‘We have known for a long time that passive muscle forces are important for the movements of small limbs, but we did not expect that their effect is so great that they can determine the speed profile of a movement. This means that the active muscle and its opponent must be perfectly tuned to each other. We are in the process of better understanding this interaction.’

Crickets, not evil Cuban commies, ‘attacked’ US diplomats


Anurogryllus celerinictus cricket, photo by Brandon woo

Translated from Dutch NOS TV today:

Crickets in love behind ‘sonic attack’ at the US American embassy in Cuba

Who or what is behind the mysterious ‘sonic attacks’ that took place at the United States embassy in Cuba? Diplomats who stayed there between the end of 2016 and the end of 2017 were faced with unexplained health problems, such as hearing loss, headaches and nausea. According to the United States, Cuba was the instigator: it supposedly carried out attacks with sound waves.

The truth now seems a little more innocent. An American and a British scientist conclude after examining a sound recording that there is no question of an audio weapon, but of crickets during their mating season.

“I can almost certainly say that the released recording is a cricket, and we think we know what species it is”, says one of the researchers to The New York Times. It is Anurogryllus celerinictus, a cricket species that lives in the Caribbean.

The researchers came to this conclusion after studying a sound recording that was published in 2017 by news agency AP. At the time, various media, including the NOS, wrote that the sound “most closely resembles the chirping of crickets“. …

The ‘sonic attacks’ affair escalated sharply at the end of 2017. The US withdrew more than half of the staff of its embassy in Havana. No visa applications were processed at the embassy, ​​and a negative travel advice for Cuba was introduced for Americans. Cuban diplomats in the US also had to leave the country. Cuba denies any involvement in an ‘attack’.

New grasshopper species discovery in the Netherlands


The new grasshopper species, photo by Zomer Bruin/Vroege Vogels

Translated from Dutch NOS TV today:

In a city park in Amersfoort, a grasshopper species, new for the Netherlands, has been discovered. Bat expert Summer Brown, during a search for bats, accidentally stumbled upon the Cyrtaspis scutata grasshopper, according to the NPO Radio 1 program Vroege Vogels.

The bright green Cyrtaspis scutata originates in countries around the Mediterranean Sea. Presumably the animal has traveled along with imported trees and has managed to establish itself here permanently.

The bat expert discovered the new species when he was looking for bats in Amersfoort’s Randenbroek park. Since 2016, he heard a sound that he thought was the brown long-eared bat. Now the sound turns out to come from the grasshopper species.

Winter

Grasshopper expert Baudewijn Odé says in Vroege Vogels that it is special that a species from the warm Mediterranean region is able to establish itself permanently in the Netherlands.

It is also noticeable that Cyrtaspis scutata is still active in winter, while the ‘regular’ Dutch grasshopper do not stay that way.

Dinosaur age baby lacewings discovery


This is a 2010 video of the lacewing taken from the BBC’s Life in the Undergrowth documentary series.

From the University of Oxford in England:

Newborn insects trapped in amber show first evidence of how to crack an egg

Amber preserving newborns, egg shells, and egg bursters shows that the hatching mechanism of green lacewings was established at least 130 million years ago

December 20, 2018

Fossilised newborns, egg shells, and egg bursters preserved together in amber provide the first direct evidence of how insects hatched in deep time, according to a new article published today in the journal Palaeontology.

One of the earliest and toughest trials that all organisms face is birth. The new findings give scientists evidence on how tiny insects broke the barrier separating them from life and took their first steps into an ancient forest.

Trapped together inside 130 million-year-old Lebanese amber, or fossilised resin, researchers found several green lacewing newborn larvae, the split egg shells from where they hatched, and the minute structures the hatchlings used to crack the egg, known as egg bursters. The discovery is remarkable because no definitive evidence of these specialised structures had been reported from the fossil record of egg-laying animals, until now.

The fossil newborns have been described as the new species Tragichrysa ovoruptora, meaning ‘egg breaking’ and ‘tragic green lacewing’, after the fact that multiple specimens were ensnared and entombed in the resin simultaneously.

“Egg-laying animals such as many arthropods and vertebrates use egg bursters to break the egg surface during hatching; a famous example is the ‘egg tooth’ on the beak of newborn chicks”, explains Dr Ricardo Pérez-de la Fuente, a researcher at Oxford University Museum of Natural History and lead author of the work. “Egg bursters are diverse in shape and location. Modern green lacewing hatchlings split the egg with a ‘mask’ bearing a jagged blade. Once used, this ‘mask’ is shed and left attached to the empty egg shell, which is exactly what we found in the amber together with the newborns.”

Green lacewing larvae are small hunters which often carry debris as camouflage, and use sickle-shaped jaws to pierce and suck the fluids of their prey. Although the larvae trapped in amber differ significantly from modern-day relatives, in that they possess long tubes instead of clubs or bumps for holding debris, the studied egg shells and egg bursters are remarkably similar to those of today’s green lacewings. Altogether, they provide the full picture of how these fossil insects hatched like their extant counterparts, about 130 million years ago during the Early Cretaceous.

“The process of hatching is ephemeral and the structures that make it possible tend to disappear quickly once egg-laying animals hatch, so obtaining fossil evidence of them is truly exceptional”, remarks Dr Michael S. Engel, a co-author of the study from the University of Kansas.

The Tragichrysa ovoruptora larvae were almost certainly trapped by resin while clutching the eggs from which they had freshly emerged. Such behaviour is common among modern relatives while their body hardens and their predatory jaws become functional. The two mouthparts forming the jaws are not interlocked in most of the fossil larvae, which further suggests that they were recently born.

All the preparations studied were obtained from the same amber piece and are as thin as a pinhead, allowing a detailed account of the fossils and finding the tiny egg bursters, according to Dr Dany Azar, another co-author of the work, from the Lebanese University, who discovered and prepared the studied amber samples.

It would seem reasonable to assume that traits controlling a life event as crucial as hatching would have remained quite stable during evolution. However, as Dr Enrique Peñalver of the Spanish Geological Survey (IGME; Geomining Museum) and co-author of the work explains: “There are known instances in modern insects where closely related groups, even down to the species level, show different means of hatching that can entail the loss of egg bursters. So, the long-term stability of a hatching mechanism in a given animal lineage cannot be taken for granted.”

Nonetheless, this new discovery in fossil green lacewings shows the existence 130 million years ago of a sophisticated hatching mechanism which endures to this day.

Stick insect evolution, new research


This 13 December 2018 video is called The Evolution of Insects (part 1): stick insect, mantis, cicada.

From Frontiers in Ecology and Evolution:

Stick insects: Egg-laying techniques reveal new evolutionary map

December 19, 2018

Known for exceptional mimicry, stick insects have evolved a range of egg-laying techniques to maximize egg survival while maintaining their disguise — including dropping eggs to the ground, skewering them on leaves, and even enlisting ants for egg dispersal. Scientists have now combined knowledge on these varied techniques with DNA analysis to create the best map of stick-insect evolution to date. Contrary to previous evolutionary theories based on anatomical similarities, the new analysis finds the first stick insects flicked or dropped their eggs while hiding in the foliage. It also finds that geographically isolated populations of stick insects are more likely to be related than those with similar features. The research, published in a special issue on stick insects in Frontiers in Ecology and Evolution, takes us one step closer to understanding these enigmatic creatures.

“While the evolutionary history of most insect groups is well documented, stick insects have been hard to classify. Our new analysis has made great strides, showing that the evolution of stick and leaf insects cannot be solely based on anatomical features”, says Dr James A. Robertson, based at the Animal and Plant Health Inspection Service and affiliated with the Brigham Young University, USA. “Linking their wide-variety of egg-laying techniques to their evolutionary history, we find that flicking and dropping eggs is the oldest strategy from an evolutionary perspective.”

Stick insects are increasingly popular in the pet industry on account of their remarkable size, bizarre appearance and gentle nature. They are the only insects where each species has an individual egg form. In the 1950s, scientists based stick-insect evolutionary theories on the traditional method of examining subtle changes in anatomical features. However, this method could not explain why distantly-related species — for example those separated by faraway continents — often shared very similar features.

Using DNA analysis and linking these findings to their variety of egg-laying techniques, Robertson and his colleagues created their own map of stick-insect evolution. As well as revealing that species geographically isolated with each other were more likely to be related than species that looked similar, the results challenged previous theories on how stick-insect egg-laying strategies evolved.

“Stick-insects were thought to evolve from a ground-dwelling adult form that deposited its eggs directly in the soil. We show that ancestral stick-insects actually remained in the foliage and dropped or flicked their eggs to the ground, a technique employed by most of these insects as a strategy to remain in disguise”, explains Robertson. “The hardening of the egg capsule early in the evolution of stick insects represents a key innovation allowing further diversification.”

This hardened capsule allows the egg to survive falls from the canopy, to float on water and to pass through the intestines of birds. A further innovation, exclusive to stick insects that flick or drop their eggs, is a food-filled cap on the egg that attracts ants, who then disperse it much further than a female stick insect could achieve on her own.

Robertson continues, “Stick insects have then adapted to new micro-habitats, which involves changing how their eggs are deployed and dispersed. There are several independent examples where species have evolved to adapt to a ground or bark dwelling habitat by depositing their eggs in the soil or in bark crevasses. Other populations have independently evolved gluing strategies, with one of these diversifying further by burying their eggs, skewering them in leaves or producing a sophisticated egg sac.”

This new research demonstrates that molecular data can begin to shed light on the evolution of these enigmatic creatures, with more to be revealed.

Robertson explains, “We hope to investigate how and when key innovations in stick insect evolution occurred, how widespread these traits are and where geographically they evolved.”