For those of you not familiar with Cordyceps fungus, that’s the one that attacks insects (and other arthropods) by infecting and then spreading through the whole body. The result is something like what you see below:
Each one of those little growths is a “fruiting body” and that is where the fungus releases its spores in order to found new patches of fungus. The most famous of these kinds of fungi is perhaps Ophiocordyceps unilateralis, which infects ants and influences their behaviour. The fungus forces an ant to climb a blade of grass or a twig and then attach there until it dies. Meanwhile the fungus produces a series of fruiting bodies that release spores from the new vantage point – the height helps those spores to disperse a greater distance. Apparently fossilised plants from 50m years ago also bear the marks of these Cordyceps-related attachments by insects, suggesting that this is an old battle.
What we don’t know is the extent to which Cordyceps influences the behaviour of other hosts. I posted the image above because it is the first time that I have seen a dragonfly infected in this way. It would make more sense (to me, at least!) for Cordyceps infecting a dragonfly to make it fly upwards while the fruiting bodies are releasing spores to broadcast those offspring as far as possible. However, the only image I have seen is this one where the animal is firmly rooted to the perch.
If it was a parasite that affected dragonfly flight then it wouldn’t be the first. A few recent studies (e.g. Suhonen et al. 2010) have suggested that dragonflies infected with parasitic mites that cling to the outside of the animal result in greater movement. It has been suggested that this could be an attempt to get out of an area with a high parasite population – after all, that’s not a great place to raise your little dragonfly family. However, we think this response has evolved to help the host and not the parasite, which is the opposite to the response elicited by the manipulative Cordyceps.
Suhonen, J., Honkavaara, J., Rantala, M.J. (2010) Activation of the immune system promotes insect dispersal in the wild, Oecologia, 162 (3): 541-547.
Image credit: Paul Bertner, https://flic.kr/p/qodUNR, all rights reserved, used with permission.
I am fascinated by the field of “biomimetics” – attempting to find solutions to problems by looking to the natural world. Sometimes this involves buildings that work like termite nests, swimsuits that use tiny hooks like those found on shark skin, or Velcro that uses the same principles as seed burrs as an inspiration. However, among the most celebrated examples of biomimetics are those involving flight.
There have been a great many legends describing early attempts at flight, with perhaps the most famous being that of Daedalus and his son Icarus. Daedalus created the Labyrinth on Crete for King Minos and the king imprisoned Daedalus in a tower so that he could not spread the knowledge of labyrinth-building to other kingdoms. Daedalus escapes with Icarus, but Icarus flies too close to the sun causing the wax holding his feathers melts and he falls into the sea and drowns. Daedalus, meanwhile, reaches Sicily (750km away). Ovid’s description of the myth states that Daedalus “…flexed each [feather] into a gentle curve, so that they imitated real bird’s wings”, and so this is clearly a calculated (if legendary) attempt to mimic bird flight.Read More »
I’ve had a bit of a go at using unmanned aerial vehicles (UAVs) in the past (see this little write-up) but with mixed success. Part of the problem is that there has not been any consistent attempt to develop a technology that can be used for environmental or ecological research – just a bunch of scientists trying to MacGyver existing equipment. Now there’s Conservation Drones, who seem to be taking a slight more systematic approach, designing their own drone, spreading the knowledge around, and starting up PhD research projects to develop the tech further. Here’s an early demo of one of their models:
Here’s a fascinating example of a leopard hunting by hurling itself from a tree:
Leopards are hugely adaptable creatures and feed in a variety of ways on pretty much anything they can catch and kill from dung beetles to gorillas. Often on the African savannah they will stalk prey around dawn and dusk, pouncing from short range. It isn’t clear whether this was a regular hang out for the leopard or whether it happened to be napping in the tree when lunch walked along…
H/T Richard Conliff at Strange Behaviours
If you want to see what a hurricane looks like as it bears down on a highly populated area, here’s the view from the New York Times office in New York:
There is a webcam set up there which will refresh every 60 seconds as the storm comes in. Might an interesting spectacle when the storm makes landfall, and a fairly frightening movie when the images are compiled! Of course, this is a dangerous storm, and I wish all the residents of New York and other affected areas the best of luck. Be prepared and be safe!
Image credit: MATT ERICSON, JON HUANG/THE NEW YORK TIMES
It’s just gone midnight and I’m still in the office, frantically trying to catch up on course preparation for an undergraduate course that I am teaching (single-handedly) at the moment (the reasons I’m playing catch-up are quite exciting, but we’re embargoed right now so I’ll write more in a few weeks…). I’m busy writing Lecture 6 (to be given Monday morning) which is going to cover the role that evolution plays in conservation, but I also have to finish prepping the three hour, assessed conservation genetics computer lab for tomorrow, write up all the feedback for the last bunch of assignments and set up the second assignment through the online learning management system so that students can actually submit the assignment… I’m tired and hungry and I would really rather be home, so I dreaded an email that I just received.
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Intelligence can be defined as the ability to solve novel problems. In other words, many examples of “animal intelligence” wouldn’t count because of the limited range of situations within which they are able to act. Examples might include squirrels caching nuts and finding them again or the ability of drongos to mimic the alarm calls of meerkats to scare them off and steal their food. A true demonstration of intelligence requires that an animal be able to solve a problem with which it has no familiarity. The kea is an example of an animal that has a remarkable capacity to do just this (h/t Jerry Coyne):
Some of you may have noticed that some things about the world are a bit depressing. Economic crises, unemployment, famine, poverty, disease… There isn’t much that we can do about these things as individuals, but there are some initiatives up and running that might help to make the world a slightly less depressing and slightly more awesome place to live in.
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