Hot answers tagged entomology
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Off the top of head as a medical professional I can imagine the following mechanisms (everything is just speculative reasoning):
Insects don't have blood. Instead, they have hemolymph whose primary role is not oxygen transport (they have an additional tracheal system for this purpose), but rather that of nutrients. Thus they don't need (and don't have) an ...
18
There are instances of insect muscle growth in response to increased use. The flight muscles of the tsetse fly (Glossina morsitans) have been observed to grow at a faster rate when subjected to enforced exercise (Anderson and Finlayson, 1976). Also larger mandibular adductor muscles (which power the feeding apparatus), and associated head capsule have been ...
18
Dickinson (2005) has a good review of insect flight, including behavior, biomechanics, electrophysiology, and neural control with links to more of the primary literature. What follows is a general summary thereof.
The jagged trajectories you mention are called saccades in the insect flight literature. In Drosophila, saccades are ~90° turns accomplished in ...
14
Holometaboly is believed to have evolved only once (Labandeira, 2011), but is arguably the most successful mode of development we know of in terms of species richness (Kristensen, 1999 - PDF link). Insects which have adopted this method are far more diverse than their hemimetabolous counterparts. A conservative estimate by Hammond (1992) is that ...
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There will always be a tradeoff in terms of resource allocation between reproduction and self maintenance. Since worker ants forego reproduction to perform other roles (gathering resources, caring for young etc.) within the colony, it makes sense that this would favour a longer lifespan. This idea works for most animals (i.e. higher reproduction = lower ...
12
Certainly ants evolved from insects that could fly. All the earliest wasps (ants are specialized wasps) could fly.
Building and maintaining wings is expensive in terms of energy. That's an obvious evolutionary advantage to not having wings. So if there's insufficient benefit from having wings then there's selective pressure against having wings.
10
Studies of Deinococcus radiodurans, the most radioactively tolerant microorganism we know, show that it has many genes for DNA repair.
In the case of the cockroach, I would assume that in addition to repairing genes, and maybe some antioxidants produced in the cells to quench free radicals produced by radiation, the fact that the roaches lay many, many ...
10
Insect flight muscle is capable of achieving the highest metabolic rate of all animal tissues, and this tissue may be considered an exquisite example of biochemical adaptation.
Locusts, for example, may (almost instantaneously) increase their oxygen consumption up to 70-fold when starting to fly. In humans, excercise can increase O2 consumption a maximum ...
8
The smaller an animal is the easier it becomes for it to fly. That is because surface area increases to the second power of the diameter of the animal whereas mass increases to the third. So the larger a thing is the more mass per surface are it has.
And since insects tend to be small they tend to be good at flying.
As for any other reason, I don't think ...
7
I'm not 100% sure, but I think they look like scale insects (Coccoidea). In particular it looks at bit like a hermaphrodite cottony cushion scale insect (Icerya purchasi)...
The white fluffy thing underneath the insects is the ootheca (egg case). The mature insect migrates to the main trunk of its host tree and attaches to the bark. It then secretes the ...
7
Wootton (1992) reviewed the anatomy and biomechanics of insect wings. Basically the wing is a lightweight but strong scaffolding of veins, supporting a thin membrane. The veins are composed by a sandwich of cuticle with a potential space in between. The membrane is also a double-layer but without the space.
In the venous space are is circulating hemolymph ...
7
The cocoon phase allows lepidopterans (and other holometabolous insects) to reorganize their body and undertake the dramatic metamorphosis from larvae to adult in a safe environment. Cocoons and pupae are typically attached to branches by silk (oftentimes after climbing high into the canopy), thereby removing them from many predatory interactions and ...
6
I don't have a definitive answer, but I suspect Hymenoptera is "just a name," albeit a name that has lasted through the phylogenetic nomenclature revolution.
Hymenoptera was erected by Linnaeus in the 10th edition of Systema Naturae (1758). The description of Hymenoptera (membrane wing; p. 553 [hope your Latin is better than mine]) follows that of ...
6
Quick search - Some articles that may interest you:
1) Random walk model of insect movements
Kareiva P. M., Shigesada N. (1983). Analyzing insect movement as a correlated random walk. Oecologia 56(2-3) 234-238
2) Artificial life model of flying insects and its comparison to real insects navigation strategies.
Dale K., Collett T. C. (2001). Using ...
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The sense of depth is required to us to orient ourselves in a 3D world. Insects do orient themselves in the exterior 3D world, thanks to the ability to detect the plane of sunlight polarization, that is used as a navigation compass in foraging expeditions and when coming back home.
You can find a good review on Current Biology (Krapp 2007) and a lecture ...
6
The main difference between tracheal gas exchange, and other forms of gas exchange (except simple diffusion) is that it is generally a passive process. Organisms with lungs, gills, or other modified respiratory organs can actively pump the oxygen-containing medium (usually air or water) across their respiratory surface, and some also pump their blood across ...
6
I don't think it's a silly question, but it is a common error to anthropomorphise animals.
Insects respond to cues which they have evolved to respond to, and this is how they 'make decisions'. They do not have free will or any more complex decision-making process like common sense. This is evident is lots of insect behaviour: flying repeatedly at a closed ...
6
Flies can and do evolve quickly thanks to a short generational time. However, your question seems to stem from a misunderstanding of what evolution entails.
Evolution occurs when the genome mutates. Why it mutates isn't particularly relevant, but a gene (or genes) mutates and as a result of that mutation a characteristic of the organism changes. It doesn't ...
6
Building on Noah Snyder's answer…
Having wings could also be expensive in other ways. For example, energy aside, maybe the growth of wings relies on some special nutrients, which were scarce in the environment of the first ancestors of modern ants. So the ant colonies that grew smaller wings (or no wing at all) thrived.
Having wings could also cost them ...
6
I do not know of any solitary ants, but there are species that form very small colonies.
One such species is Jerdon's Jumping Ant (Harpegnathos saltator). They usually live in colonies smaller than 100 individuals and workers may reproduce, so the colony can survive after the queen's death.
5
Take a look at Ramasubramanian et al.[1] The authors have some great SEM images of the proboscis and fascicle tip and derive a mathematical model for the "bite" itself.
They mention that there are two types of feeding: pool feeding, where the mosquito creates a hemmorrhage and feeds slowly via capillary action, and capillary feeding, wherein the mosquito ...
5
Insects breathe by simple diffusion through the cell walls. They do not breathe in the same sense that we humans do. They intake oxygen through spiracles in the insects skin. It goes through the insects trachea by dissolving into the tracheal liquid. From there it diffuses throughout the insect in tracheal tubes. At the ends of the tubes, the oxygen is taken ...
5
"1001 questions answered about insects" by Alexander Barrett and Elsie Broughton Klots includes the following passage:
Do insects have depth perception? Depth perception of some sort is important to an animal who has to catch its prey; fortunately most
insects have it to a degree. Although they do not have binocular
vision that can be compared with ...
5
The species of wasp you're referring to is Glyptapanteles. I'm not sure which virus it is.
http://www.newscientist.com/article/dn14053-zombie-caterpillars-controlled-by-voodoo-wasps.html?feedId=online-news_rss20
Is it possible? Of course, you have an example! Though, there is a small caveat. Some of the offspring sacrifice themselves to induce the ...
5
I think the answer to your question is relatively unknown. The answer I have heard the most often, which is largely the most accepted, is that many insects orient themselves in space using light. So if they are flying at night, the soft light of the moon tells them which relative direction they are going. Light bulbs end up confusing them, because they think ...
5
Insects and spiders have tremendous sexual dimorphism, with males often being much smaller than females. They are pretty much just sperm carriers and sometimes do not eat. Insects may have two or one sex chromosome, where males my have only one chromosome. As is pointed out in the comments, not all mantis' species display this dimorphism.
Since such ...
4
Insects and vertebrates are extremely distantly related: they're on opposite sides of the oldest split among bilaterally symmetric animals. Their most recent common ancestor lived in the pre-cambrian and was almost certainly worm-shaped with no limbs at all. There's no way that insect wings are homologous to any body parts of vertebrates.
The evolution of ...
3
"in the long run we're all dead men" - John Keynes
First is the fact that flies have adapted their way around cars long long ago by giving up longevity for faster breeding; flies are cheap and they just don't care if they get hit by a car. The average flying insect lays large clutches of eggs - hundreds at a go is common. See this reference on butterflies ...
2
After seeing your question, I decided to do a bit of research on the topic.
First Source: EurekAlert!
http://www.eurekalert.org/pub_releases/2007-04/jws-mrt041607.php
"Mosquito repellents that emit high-pitched sounds don't prevent
bites"
Some key-points from the webpage:
A Cochrane Systematic Review of the use of electronic mosquito ...
2
When is it good to have wings?
When you need to move a great distance in as short a time as possible with minimal risk.
Clearly wings would have enormous benefit at a time when you need to get far away from the nest really quickly, perhaps at a time when you believe the weather would be particularly favourable. This benefit increases exponentially when ...
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