Did you know it’s National Insect Week? Organized every two years by the Royal Entomological Society, National Insect Week encourages people of all ages to learn more about insects. To improve your insect knowledge, we’ve selected some of our favourite insect-based papers from the past few months.
The authors of this paper created an insect–computer hybrid robot, or Cyborg Insect. Electrodes were implanted into the legs of beetles and individual muscles were stimulated in predefined sequence using a microcontroller. The step frequency and walking speed were successfully controlled, and the authors also demonstrated different walking gaits. This is the first paper to show a living insect moving under users’ control.
Leaf-cutting ants are highly social insects and waste disposal is crucial to prevent infections, but did you know that the location of waster dispersal varies according to the species? Some use external refuse piles and others bury it inside underground chambers. The authors of this Proceedings B paper studied whether environmental conditions and evolutionary history can explain the differing location of waste by leaf-cutting ants. They found that species living in humid habitats (suitable for pathogens) are more likely to locate waste inside internal refuse chambers, whereas species living in much drier conditions (less suitable for pathogens) are more likely to dump waste in external refuse dumps. This shows how sanitary behaviours can result from a combination of evolutionary history and current environmental conditions.
Bumblebee obstacle course
The wings of foraging bumblebees frequently collide with vegetation, and over time these collisions can cause wings to wear down. Wing wear increases mortality in bumblebees, but the mechanism by which this occurs has remained a mystery. Andrew Mountcastle and colleagues from Harvard University tested the hypothesis that wing wear increases predation risk by reducing flight maneuverability. They challenged bees to fly through a moving obstacle course designed to push them towards their performance limits, and found that wing wear decreases peak accelerations during maneuvering flight, which may constrain the ability of a bumblebee to escape from aerial predators.
Bumblebee obstacle course: sample flight trial
Natural disasters, breaks in transportation networks, outbreaks of disease and other events disrupt human infrastructure, such as our transportation, communication and supply chain networks. These networks are deliberately planned, complex, and highly coordinated. Social insects, such as bees, experience similar disruptions yet their networks are not deliberately planned; rather, individual insects make simple decisions based on local information. This review, published in Journal of the Royal Society Interface, examines these leaderless but complex systems and identifies factors that lead to infrastructure resilience and collapse. Human infrastructure networks are becoming increasingly decentralized and interconnected, so perhaps our deliberately planned networks can benefit from the lessons of social insect resilience.
Termites are social insects, whose colonies consist of very fertile reproductives with long lifespans – the king and queens – and of short-lived and sterile individuals – the workers and soldiers. David Sillam-Dussès and colleagues from the University of Paris show that the Carbohydrate-Responsive Element-Binding Protein, known in vertebrates to regulate glucose metabolism, also plays an important role in signaling of fertility to maintain the reproductive monopoly of the queen in termite colonies.
Can insects repair their bones? Biomechanics researchers Prof David Taylor and colleagues at Trinity College Dublin discovered that, if you cut the leg of an insect, it will make a patch of new material underneath the cut which acts as a kind of internal bandage. Unlike us, insects cannot completely repair their bones, but it turns out that, using this patch, they can do a pretty good job, restoring 66% of the original, intact strength and allowing them to keep using the leg for normal activities.
Due to their comparably small sizes, insects face fatal problems in their environment: a drop of water or the morning sun can kill a new-born caterpillar by suffocation or desiccation, respectively. To protect themselves against natural hazards, they have developed a two-sided lipid-based coat, called the cuticle. The properties of this coat protecting against transpiration have been well studied, but little is known about its distribution and organization. This paper shows that different regions of the cuticle may have different, temperature-dependent protective properties against penetration of xenobiotics, and it appears that this feature varies in different insect species. This knowledge may serve to design and optimize species-specific insecticides.
A key question in reproductive behavior is how to generate more and healthier progenies by choosing optimal mates. In flies, males use multiple sensory cues including vision, olfaction and gustation to achieve reproductive success. These sensory inputs are important but their specific roles in male courtship preference remain largely unknown.
This Open Biology paper reveals that dysfunction of an olfactory receptor Or47b rendered males unable to discriminate younger mates from older ones. In combination with previous work showing that gustatory perception of required for reproductive preference, this recent development demonstrate the requirement of both olfaction and gustation in male courtship preference of flies, thus providing new insights into the role of sensory cues in reproductive behavior and success.
Net-casting spiders from the genus Deinopis possess the largest eyes of any spider. Past research has implicated the importance of vision in the nocturnal foraging habits of Deinopis, but no direct link between vision and foraging has been made. Until now. The authors tested this by conducting visual occlusion trials in both natural and laboratory settings. Their results show that Deinopis spinosa relies heavily on visual cues detected by the enlarged eyes to capture walking prey items. They also suggest that the big eyes not only increase diet breadth, but allows spiders to remain active solely at night, thus evading predation by daytime animals.
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