BOOK NOTE: I interrupt this book review to note that Genius: The Life and Science of Richard Feynman
Garden Insects of North America: The Ultimate Guide to Backyard Bugs
Tag Archives: Insects
How Does the Asian Fruit Fly Ruin Crops? And How Do We Stop It?
There is some interesting new research out on the Asian Fruit Fly, Drosophila suzukii.
The short version: This sort of fruit fly ruins fruit crops because it prefers to, and is able to, lay its eggs on harder, firmer, unrotten, and, essentially, ripe fruit, thus ruining it. Regular fruit flies focus on rotten fruit such as groundfall.
The Asian fruit fly manages this because of slightly different fruit detection mechanisms, though some of the details of this are not yet known. In the future, it is hoped that the exact chemical used by this fly to find its target ripe fruit can be reproduced and used in the manufacture of a bait, to reduce crop damage.
The paper is:
Evolution of multiple sensory systems drives novel egg-laying behavior in the fruit pest Drosophila suzukii, Marianthi Karageorgi, Lasse B. Bräcker, Sébastien Lebreton, Caroline Minervino, Matthieu Cavey, K.P. Siju, Ilona C. Grunwald Kadow, Nicolas Gompel & Benjamin Prud’homme. Current Biology, 9 March 2017.
From the press release:
The Asian fruit fly Drosophila suzukii reached Europe and the US about a decade ago. This invasive species ravages fruit crops, including strawberries and cherries, and there is currently no effective means of staving it off. Unlike other drosophilae, which lay eggs on rotting fruits, D. suzukii chooses ripe fruits, thereby accelerating their decomposition. Researchers from the Developmental Biology Institute of Marseille (CNRS / AMU) and LMU Munich recently discovered that D. suzukii has developed greater sensitivity to the smell and taste of ripe fruit, in comparison to fermented fruit, and the ability to lay eggs in relatively firm fruit. By selectively inactivating the fly’s neurons and olfactory receptors, they demonstrated that the smell of fresh fruit enhanced D. suzukii egg laying. The scientists are now trying to identify the molecule or molecules that elicit this response. This would then make it possible to develop bait or design molecules that could inhibit egg laying. The results of their work also offer insight into how instinctive behaviors like egg laying are altered in the course of evolution.
How ants navigate homeward – forward, backward, or sideward
I’ve got this press release that will be of interest to many:
An international team including researchers at the university of Edinburgh and Antoine Wystrach of the Research Centre on Animal Cognition (CNRS/Université Toulouse III—Paul Sabatier) has shown that ants can get their bearings whatever the orientation of their body. Their brains may be smaller than the head of a pin, but ants are excellent navigators that use celestial and terrestrial cues to memorize their paths. To do so, they use several regions of the brain simultaneously, proving once again that the brain of insects is more complex than thought. The researchers’ findings were published in Current Biology on January 19, 2017.
Until now, ethological research suggested that ants memorized the scenery perceived along their route as it is projected on their multifaceted retinas—thus using a body-centered, or egocentric, frame of reference. By this hypothesis, to recognize memorized surroundings and follow a path formerly traveled, ants would need to orient their bodies in the same way each time. But they sometimes need to walk backwards as well, and this doesn’t prevent them from finding their way back to their nest. Could it be that ants can recognize a route when facing the opposite direction? Are they able to create a visual model of their environment that is independent of their body orientation?
To answer these questions, the researchers studied Cataglyphis velox, an Andalusian desert ant known for its solo navigation ability. First they let the insects familiarize themselves with a route that included a 90° turn. After a day of training, ants that received a cookie crumb light enough to carry while walking forward handled the turn without the slightest difficulty. However, those given large cookie crumbs had to move backward, and unlike the others, they maintained their bearing instead of turning.
They also exhibited unexpected behavior: After walking backward a bit, they would occasionally drop their crumb, turn around, observe the scenery while pointing their bodies in the right direction, return to the crumb, and resume towing it backward – but this time in the correct direction. For these ants, body alignment thus seems necessary for recognition of scenery perceived by their retinas, but they are then able to memorize the new bearing and follow it backward. This behavior also shows that they can recall the existence of the dropped cookie crumb, and its location, in order to return to it after updating their bearing. These observations imply that at least 3 kinds of memory are working in unison: the visual memory of the route, the memory of the new direction to follow, and the memory of the crumb to retrieve.
Through another experiment using a mirror to reflect the sun1, the team demonstrated that the ants used celestial cues to maintain their bearing while walking backwards. Furthermore, ants were able to move in straight paths, whether walking forward, backward, or sideways. Once a bearing is memorized, they stay on it no matter how their bodies are oriented. Together these observations suggest that ants register direction using an external – or allocentric – frame of reference.
These new findings show that the ants’ spatial orientation relies on multiple mental representations and memories woven together through a flow of information between several areas of their brain. This offers a whole new perspective on the world of insects, which is much more complex than previously believed.
How do insects walk on water?
A new study illuminates this shadowy question. First, the video:
And now, a press note from the American Chemical Society:
Water striders’ ability to walk and jump on the surfaces of ponds and lakes has long amazed curious observers — and inspired robot designers who want to mimic the bugs’ talent. Now, scientists have measured for the first time key parameters that allow them to walk on water — by studying their leg shadows. The findings, reported in the ACS journal Langmuir, could contribute to designs for water-skimming robots.
More than 2,000 years ago, Greek scientist Archimedes explained flotation, stating that the upward, floating force on an object in water equals the weight (or downward force) of the water displaced. The principle has informed the building of ships, submarines and other aquatic vehicles. But for tiny water striders, water isn’t displaced. It is expelled by the insect’s hairy legs. The updated Archimedes principle predicts that the weight of the expelled water should equal the floating force. But confirming this prediction experimentally is a challenge. Because water striders are so light, they are almost impossible to weigh using conventional techniques. So Yu Tian and colleagues used an unconventional method — analyzing the shadows cast by the insects’ legs.
The researchers placed a white sheet of paper at the bottom of a lab aquarium housing water striders and installed a light source above the water. The insects’ stick-straight legs cast shadows that were rounded, representing the curvature of the water and the expelled water volume from which the floating force and weight can be calculated, the researchers say. Also, from these measurements, the striders’ slightest shifts in weight and body angle could be detected for the first time.
The authors acknowledge funding from the National Natural Science Foundation of China.
The abstract from the original publication:
Forces acted on legs of water-walking arthropods with weights in dynes are of great interest for entomologist, physicists, and engineers. While their floating mechanism has been recognized, the in vivo leg forces stationary have not yet been simultaneously achieved. In this study, their elegant bright-edged leg shadows are used to make the tiny forces visible and measurable based on the updated Archimedes’ principle. The force was approximately proportional to the shadow area with a resolution from nanonewton to piconewton/pixel. The sum of leg forces agreed well with the body weight measured with an accurate electronic balance, which verified updated Archimedes’ principle at the arthropod level. The slight changes of vertical body weight focus position and the body pitch angle have also been revealed for the first time. The visualization of tiny force by shadow is cost-effective and very sensitive and could be used in many other applications.
Citation: Yelong Zheng, Hongyu Lu, Wei Yin, Dashuai Tao, Lichun Shi, and Yu Tian. 2016. Elegant Shadow Making Tiny Force Visible for Water-Walking Arthropods and Updated Archimedes’ Principle. Langmuir 2016 32 (41), 10522-10528. DOI: 10.1021/acs.langmuir.6b02922
The European Honey Bee Shortage
Bioscience for the future has an update o the bee situation in Europe.
Europe has 13.4 million too few honeybee colonies to properly pollinate its crops, according to new research from the University of Reading.
The discovery, made by scientists at the University’s Centre for Agri-Environmental Research (CAER), shows that demand for insect pollination is growing five times as fast as the number of honeybee colonies across Europe as farmers grow more insect-pollinated oil crops, such as oilseed rape and sunflowers, and fruit.
Click here to read all about it.
Here’s a video:
Published on Jan 8, 2014
Europe has 13.4M too few honeybee colonies to properly pollinate its crops, according to new research from the University of Reading.
The discovery, co-funded by BBSRC and made by scientists at the university’s Centre for Agri-Environmental Research (CAER), shows that demand for insect pollination is growing five times as fast as the number of honeybee colonies across Europe as farmers grow more insect-pollinated oil crops, such as oilseed rape and sunflowers, and fruit.
More on honey bees and related topics.
Bug Girl writes a lot about this topic.
Carl Zimmer on honey bee colony collapse
The Magic of Butterfly Scales (and Pixie Dust)
This is a cool two part Youtube video that explains a lot of interesting science.
Part I:
Part II:
Honey Bee Colony Collapse Disorder
We recently discussed news from the EU on banning neonicotinoid pesticides in order to stem the so called Colony Collapse Disorder (CCD) among honey bees. Bug Girl has an important guest post on the phenomenon of CCD by bee expert Doug Yanega. This is a must read not only for those interested in bees and CCD, but skepticism and science reporting in general, as Yanega places the current discussion in a strong historical context and provides a valuable critique of much of the reporting on CCD. Go read Honey bees, CCD, and the Elephant in the Room.
Photo Credit: wildxplorer via Compfight cc
EU will ban neonicotinoid pesticides to save the honey bees
Being a bee is hard. I’m speaking specifically of the honey bee, Apis mellifera, the one that produces the honey you buy in the store. Many insects, and other critters, eat by finding food and then eating it, and then they do that for a while and now and then reproduce by finding a mate, laying eggs that they perhaps put in a good location but thereafter leave alone, etc. etc. But honey bees do all of these thing in a way that makes it seem like they are trying to make it harder for them than it is for everyone else. Much of the food that honey bees eat is gathered at rare and hard to find sites (flowers), carried back to a central place that may be quite far away, then processed. Offspring are produced by a very small subset of a large colony, using a system involving several individuals who make places for the queen to lay the eggs around. Larvae are then taken good care of and fed. This whole thing takes place in a hive which can only be effectively placed in one of a limited number of locations. Since there is processed food (honey) and larvae (also good to eat) all in one place, the bee colony must have multiple ways of protecting itself, including picking a good location, making the hive hard to get into, and having a hoard of suicidal stingers ready to die in defense of the nest. Beyond this, sneaky invaders, other insects that might try to sneak into the hive, must be identified by guards.
Navigation over long distances, communicating with other bees about newly found hard to get and far away sources of food, mechanisms of controlling reproduction within the colony, thermoregulation of the hive, building and maintaining architecture, species recognition, a mechanism of changing behavior among a number of different tasks (thermoregulation, foraging, building the hive, attacking selected invaders, swarming) … Yeah, being a honey bee is hard.
Colony Collapse Disorder (CCD) is a thing where the colonies of bees in a given area are affected by something that causes the number of bees to reduce in population over time … the worker bees seem to disappear … so the colony dies. Think about all the things I mentioned above. Any small subset of these things could be disrupted to cause something like CCD. The transfer of information about where to go to find food, and the process of foraging and navigating to food sources and back involves a lot of different mechanisms; the disruption of any one or two of those mechanisms might cause worker bees to fly off and not come back. The process of foraging at distance and carrying back food requires a great deal of energy. Any part of the process of maintenance and distribution of food to worker bees could cause them to starve or reduce in energy level, causing them to not return to the hive. Leaving most of these tasks and mechanisms untouched and operational but adding a pathogen that demands more energy from individual bees could have a similar effect. In other words, in the absence of any good information about what causes CCD, it would be very hard to come up with a simple explanation for that phenomenon on the basis of what bees do normally. The phenomenon can also be caused by any two or three of a dozen things, such that the cause in any given case could be very different from the cause in a different case.
To this we can add another feature of honey bees. For the most part, we are talking about bees that are not living in their native habitats. Our honey comes from a subset of honey bees that have been to varying degrees domesticated, and that are living in a climate that is not where they originally evolved. Imagine going to a region where chickens are grown but that is environmentally very different from the region where a chicken like bird lives normally, and deleting one or two of the key things we do to keep those chickens alive. I.e, leave all the chickens out for the winter in Montana. Not feed them. Etc. There would be “Coop collapse disorder” in no time. The fact that honey bees exist in a sort of liminal state of wildness (they forage in the wild, although the “wild” may be human maintained farm fields and orchards) and domestication (their hives are generally built and maintained by humans who may also provide heat and protection from predators) together with the fact that honey bees have undergone some degree of selection (to make them a bit less fierce, for instance) may mean that the complex web of physiological and behavioral adaptations that make bees “work” properly is somewhat more delicate than it might be for wild bees living in their native tropics.
I don’t mean to give the impression that bee experts have no idea what causes CCD. They do have ideas, evidence, and there has been a fair amount of research done (below are links to a few key blog posts that summarize much of this). The point I’m making here is that the complexity of CCD and the difficulty in understanding this phenomenon should not be a surprise.
Just now, the European Union has decided to implement a regulation that bans a certain kind of insecticide, neonicotinoid, from use in their purview, because it is possible that this insecticide has a negative impact (perhaps multiple negative impacts) on bees, contributing to CCD. This may be a good idea, even if the insecticide in question is not “the” primary cause of CCD, if the chemical simply makes CCD a much more likely thing to happen. Banning it may be like giving a patient with some horrid infection an IV of fluids. The IV is not directly treating the infection, but the patient may require the support provided by the IV (and other things they do for you in a hospital, like the great food and a TV strapped to the ceiling) may be what it takes to allow other treatments, or the patient’s own immune system, to bring the individual to a state of better health.
The ban was not universally supported. Voting against the bad were the United Kingdom, the Czech Republic, Italy, Hungary, Romania, Slovakia, Austria and Portugal; voting for the bad were Belgium, Bulgaria, Denmark, Estonia, Spain, France, Cyprus, Germany, Latvia, Luxembourg, Malta, the Netherlands, Poland, Slovenia and Sweden. Ireland, Lithuania, Finland and Greece abstained. This resulted in a vote that would not automatically institute the ban, but a decision by the controlling commission to move forward with the ban was made possible, and that is what has happened. The ban will run for two years and apply to flowering crops that normally attract bees. In a way, this is more of a giant experiment than an actual ban.
The Guardian reports:
Europe will enforce the world’s first continent-wide ban on widely used insecticides linked to serious harm in bees, after a European commission vote on Monday.
The landmark suspension is a victory for millions of environment campaigners concerned about dramatic declines in bees who were backed by experts at the European Food Safety Authority (EFSA). But it is a serious defeat for the chemical companies who make billions a year from the products and also UK ministers – who voted against the ban. Both had argued the ban will harm food production.
…
Tonio Borg, health and consumer commissioner, said: “Our proposal is based on a number of risks to bee health identified by the EFSA, [so] the European commission will go ahead with its plan in coming weeks. I pledge to do my utmost to ensure that our bees, which are so vital to our ecosystem and contribute over €22bn annually to European agriculture, are protected.”
It is almost certainly not the case that bee researchers unanimously agree that neonicotinoid is the most important cause of CCD or that banning it will work. Neonicotinoid is actually a good kind of insecticide because it works by being taken up by plants, and thus, targets invading insects selectively, and also, affects insects that are not bothered much by other insecticides because the insects bore into the plant. So, there may be some serious consequences to agriculture in Europe caused by this ban.
It will be interesting to see what happens over time. I’m not sure how long it will take for the ban to fully take effect. Since it is added to soil, neonicotinoid will remain “in use” for a while after it is no longer applied. And, even if neonicotinoid was a key cause of problems in bees, it is quite possible that other causes were exacerbated by neonicotinoid use, and the effects of those causes may take longer to go away or become less important.
One interesting aspect of this ban is the way in which environmental groups and the chemical companies that make the insecticide have bifurcated into two distinct ways of thinking. Again, from the Guardian:
Greenpeace’s chief scientist, Doug Parr, said [of a dissenting vote by the UK]: “By not supporting the ban, environment secretary, Owen Paterson, has exposed the UK government as being in the pocket of big chemical companies and the industrial farming lobby.”…
But a spokesman for Syngenta, which makes one of the three neonicotinoids that have been suspended, said: “The proposal is based on poor science and ignores a wealth of evidence from the field that these pesticides do not damage the health of bees. The EC should [instead] address the real reasons for bee health decline: disease, viruses and loss of habitat.”
and…
Prof Simon Potts, a bee expert at the University of Reading, said: “The ban is excellent news for pollinators. The weight of evidence from researchers clearly points to the need to have a phased ban of neonicotinoids….
vs.
“Bayer remains convinced neonicotinoids are safe for bees, when used responsibly and properly,” said a spokesman for Bayer Cropscience. “As a science-based company, Bayer is disappointed that clear scientific evidence has taken a back-seat in the decision making process.”
Both Bug Girl and Carl Zimmer have written a fair amount on this topic, and their posts include links to a great deal of additional information.
- 2012-03-29 Carl Zimmer in the New York Times: 2 Studies Point to Common Pesticide as a Culprit in Declining Bee Colonies
- 2012-03-31 Bug Girl’s Blog: Are Neonicotinoid Pesticides Killing Bees?
- 2012-05-23 Bug Girl’s Blog: Bees and Pesticides (again)
Photo Credit: Chalkie_CC via Compfight cc
How to Identify Dragonflies and Damselflies
I want to tell you about a cool book, but first, here’s something interesting about Dragonflies. Terrestrial animals (like humans) require long chain fatty acids but don’t synthesize them from basic parts. Higher terrestrial plants don’t make the biggest of these molecules either, but plants do make molecules that can be turned into things like EPA and DHA in animals. So, while terrestrial animals can get what they need by consuming other animals or by starting out with plant molecules, it is a long slog from a bunch of readily available simple molecules to large and hard to get but very important long-chain polyunsaturate fatty acids. This is why nutrition experts tell us to eat fish or fish oils. Fish have lots of these molecules already in them.
Where to the fish get them? Well, at the base of aquatic ecosystems are algae that produce these molecules. So, stuff that eats stuff that eats stuff in aquatic systems eventually eats these algae directly or indirectly. And here’s where Dragonflies come in. They hatch and mature through non-adult stages in the aquatic ecosystem. There, the Dragonfly larvae are little tiny super predators, eating other invertebrates and even tiny fish. In this manner they concentrate long chain polyunsaturated fatty acids. Then, they emerge as adult insects and fly around where terrestrial animals munch on them. In this way, these rare and important complex molecules become a bit more abundant in terrestrial systems than they otherwise might. This applies broadly to “emerging” insects that start out in an aquatic form, but in some environments the Dragonflies are a major factor. More generally, dragon flies move piles of biomass across the landscape, away from ponds and lakes where bio-molecules naturally accumulate because stuff goes down hill.
Citations for two recent research papers that discuss this are below.
And now for the book. There are over 300 species of Dragonfly and Damselfly in North America east of the Rocky mountains. Dragonflies and Damselflies of the East (Princeton Field Guides)
Paulson also has a Dragonflies and Damselflies of the West
Images provided by Princeton Press.
M. I. Gladyshev, A. Yu. Kharitonov, O. N. Popova, N. N. Sushchik, O. N. Makhutova, & G. S. Kalacheva (2011). Quantitative estimation of dragonfly role in transfer of essential polyunsaturated fatty acids from aquatic to terrestrial ecosystems DOKLADY BIOCHEMISTRY AND BIOPHYSICS, 438 (1), 708-710 DOI: 10.1134/S1607672911030094
O. N. Popova, & A. Yu. Kharitonov (1). Estimation of the carry-over of substances by dragonflies from water bodies to land in the forest-steppe of West Siberia CONTEMPORARY PROBLEMS OF ECOLOGY, 5 (2012), 49-56 DOI: 10.1134/S1995425512010043
Abstract: The results of many years’ monitoring of the number and distribution of dragonflies in the Chany area of the Baraba forest-steppe are presented. An estimation of the biomass carry-over by dragonflies from water bodies to land ecosystems is given. The data presented provide evidence of the important role of dragonflies in the migration of substances from water bodies to land.
Do Neonicotinoid Pesticides Contributed to the Complex Thing We Call Bee Colony Collapse?
A commonly used insecticide, and possibly an increasingly widely used form of that pesticide, could be a causal factor in bee colony collapse. It is not 100% certain that this pesticide’s effects can be counted as one of the causes this problem, but there is a very good chance that neonicotinoids can cause a drop in hive population, and thus, should be examined to see if there is a relationship in some cases. From the paper’s abstract:
Nonlethal exposure of honey bees to thiamethoxam (neonicotinoid systemic pesticide) causes high mortality due to homing failure at levels that could put a colony at risk of collapse. Simulated exposure events on free-ranging foragers labeled with an RFID tag suggest that homing is impaired by thiamethoxam intoxication. These experiments offer new insights into the consequences of common neonicotinoid pesticides used worldwide.
“Excuse me, there’s some food in my bugs!”
Speaking of people eating insects … as we were … I do have this fun story from the Ituri Forest.
Continue reading “Excuse me, there’s some food in my bugs!”
“We Live In Little Houses Made of Beans”
I have written before of insects in the Ituri Forest. (Oh, and here too.) When it comes up that I’ve spent time there, certain questions often come up, and one of them is: “Did you eat bugs.”
Continue reading “We Live In Little Houses Made of Beans”
The Curious World of Bugs
The old man crouched slightly as he took small tiny steps forward towards the woman’s ass. I didn’t see what was in is raised right hand, it was hidden from my view by his body draped with a colorful sarong. He crept closer, still crouched and still silent. She didn’t see him coming, but when he finally struck the woman hardly seemed to notice. His hand, it turn out, bore what looked like a hand broom of the type used to sweep the dirt floors of the mud huts and open barazas, but smaller, cleaner, and cut somewhat differently. He used it to strike a fly off her bottom and when the surprised insect hit the ground his foot sprung out as fast as a welterweight boxer’s fist mushed it to death.
Continue reading The Curious World of Bugs
Strange insect encounter: Carrion Beetle with Mites
I’ve heard of “carrion beetles” but this is more like a “carry-on beetle”:
Amanda and I were outside the cabin in Cass County, Minnesota last week, cutting pieces of plywood for sub flooring, and we saw this creature among the debris. At first I thought it was some kind of wasp covered with tiny spiders, but on further investigation it turned out to be a beetle covered with mites. When we first saw it, there were many more mites than in this photo, and they were virtually roiling on the insect’s surface. It looked almost as though the insect was foaming.
Continue reading Strange insect encounter: Carrion Beetle with Mites
An organic workout, a strange encounter, and a movie
Replacing floors is a total exercise routine. Moving furniture out of the way, ripping up whatever is there, measuring and cutting new sub flooring, carting around heavy sheets of plywood, tacking and nailing, and so on and so forth works every single muscle in one’s body. That’s what we did last weekend. Also, I was able to demonstrate my special technique for testing if a particular floor is safe, or if it is so rotted out that it has to be replaced; You stand on it bouncing up and down a little bit and if you crash through to the basement, that part of the floor was bad.
Saw the strangest insect thing we’ve seen in a long time. A wasp of some sort was covered … the entire body but not the head was covered … with little tiny things that looked like mites or itty bitty spiders or ticks or something. They were two or three thick over the wasp’s entire body. On first seeing this, I thought it was a wasp covered with bubble-bath. When Amanda first saw the insect staggering among old flooring debris, she thought it was a large drunken bumble bee, and not the lightly built wasp that it was.
(Added: It may not be a wasp. It is kind of hard to tell, being enveloped in several layers of tiny organisms and all.)
We put it in a jar so we can figure it out later.
We all sat down to watch a movie last night after a long day of prying and pounding and cutting and dragging stuff. The Informant, staring Matt Damon. I was the only one who did not drift off to sleep before the end, so I was the only one that saw the film to its rather bizarre conclusion. The movie is about one of the first major anti price fixing suits of the modern era, in the 1980s and early 1990s. It reminded me of a conversation I had with someone back in the 1970s, before any of that happened. He was an economist who worked for the international organization representing paper pulp manufacturers. He told me, with a few drinks in him and with a little too much hubris, about how price fixing worked in his industry. Apparently, he was more or less in charge of fixing production and pricing internationally for pulp manufacturers (or, at least, head organizer of this effort). He told me that the regulators would actually watch them at their international meetings (I did not know if he meant overly or covertly), so the representatives of each major pulp producing company would play it totally cool and do nothing about production and price fixing at said meetings. Then there would be a private golf game, at which the representatives of the various manufacturers would fix the prices. He was very proud of how he outsmarted to cops. I wonder if he ever got caught? Anyway, the movie was interesting, I recommend it.