// Twitter Cards // Prexisting Head The Biologist Is In: January 2016

Tuesday, January 19, 2016

Micro insects

I haven't been feeling up to writing much lately. Most of my free time has been occupied with working on an academic project in meta-genomics. I'm aiming for this to be published in a science journal, so I won't be discussing the details of it here (for now). I'm also experiencing some anxiety surrounding what my job currently is, where it is going, and where I want it to go.

All together, this is leading to a pretty solid writer's block. I've got a collection of interesting topics that I haven't managed to pull together into full posts, so I'll probably be posting a few of these over the next several weeks. Today, I want to point you towards some readings about extremely, bizarrely, tiny insects.

Micro-wasp with aneucleate nerves
Micro beetle.
Features found in both micro-insects.
  1. Reduced number of neurons, but a relatively larger nervous system.
  2. Reduction in number of organ parts. Reduction in Malpigian tubules, spicules, etc.
  1. Polilov, A. (2008). Anatomy of the smallest coleoptera, featherwing beetles of the tribe nanosellini (Coleoptera, Ptiliidae), and limits of insect miniaturization. Entomological Review 88:26-33.
  2. Polilov, A. (2011). The smallest insects evolve anucleate neurons. Arthropod Structure & Development In press. doi:10.1016.j.asd.2011.09.001
  3. Niven, J. E., and S. M. Farris (2012). Miniaturization of Nervous Systems and Neurons. Current Biology 22:R323-R329.

Tuesday, January 12, 2016

The Poison-Apple Tree

Most residents of the USA are familiar with Poison Ivy (or Poison Oak), but we're generally not familiar with a farm more poisonous tree that also lives here. The Manchineel tree (Hippomane mancinella) grows in Florida (as well as more tropical areas of the Americas) and is considered one of the most poisonous trees on the planet.

H. mancinella belongs to the Euphorbiacea, a plant family which is crowded with poisonous representatives. This tree stands out in the crowd, however. You can be poisoned by eating the fruit, touching the leaves, breathing smoke from burned wood, or even by rain splashing off upper branches. Locals tend to place large hazard signs on any tree that they know about. This doesn't stop the occasional tourist from finding one without appropriate signage, and even eating some of the sweet smelling (and tasting) fruit, before the poison begins to have its effect. Extreme pain, lesions, intestinal damage, etc. are common. Death isn't unheard of as a side effect of all this damage.

Before you go tromping around in the woods on some tropical Caribbean island, you should make a point to study up on how to identify this tree from a distance.


Tuesday, January 5, 2016

Doom of the Fruit Fly

The red-eyed fruit-fly familiar to biology students everywhere (Drosophila melanogastor) likes to lay eggs in recently spoiled fruit, where its larvae can consume the fruit sugars and the yeasts that grow on them. If you have an infestation of D. melanogastor in your kitchen, the first step is to get rid of whatever they're breeding in. The second step is to get rid of all the adults that are flying around. You could spray some poison, get skilled with a fly-swatter, or buy some commercial traps... but it is a pretty simple task to make your own trap without needing any poison. Make a paper cone with a small hole in the tip, then put it point-down into small jar with a bit of over-ripe fruit in the bottom as bait

The inverted cone prevents the fruit flies from finding their way out once they've crawled inside. If you don't have an inverted cone, you'll just be breeding more fruit flies to infest your kitchen. The bait can be whatever rotten fruit was attracting the flies.

One species of fruit-flies that doesn't like recently spoiled fruit is the Spotted-Wing Fruit Fly (Drosophila suzukii). This species lays its eggs in ripe soft fruit (raspberries, strawberries, blueberries, etc.). They are able to do this because the females have a saw-edged ovipositor that lets them cut into soft fruit to lay their eggs. They don't have to wait for fruit to begin rotting like the typical fruit flies and their infestation will result in the rapid destruction of fruit that would otherwise go to market. This has become a big problem for people trying to grow berries without pesticides. There are traps for these flies, but they're only really useful as a surveillance tool. The traps alone will not protect your fruit.

Image from blogs.cornell.edu post.
Another group of fruit-flies that don't like recently spoiled fruit are the dark-eyed fruit flies. D. repleta, D. hydei, and D. robusta are slightly larger and prefer their food source to be far more degraded. What this often means is the grimy collection of goo in floor drains or between/underneath cracked floor tiles in restaurant kitchens. It also can mean chicken poop in a barn, a mostly rotted compost pile, or the litter of a reptile tank (that I really probably should have cleaned already).

Once I noticed the existence of the flies, I cleaned up the source of the problem and my gecko is happy with her spiffy new home. The fruit-fly trap I described for D. melanogastor would work equally well for these flies if I could figure out a bait that they would be attracted to. I could scoop some of the old rotted reptile media into the jar, but I discovered something a bit more interesting (and effective).

S. integrifolium "Pumpkin Tree" fruit.
I had the branches and fruit from a Solanum integrifolium "Pumpkin Tree" plant I grew this year hanging up in our kitchen to dry. I first noticed the dark-eyed fruit-flies because they were hanging out on the branches when I checked on how the dry the fruit was. As an experiment, I put a couple of the fruit into the previously described fruit-fly trap and put the remainder of the plant outside.

The next morning, all of the flies from the kitchen were having a party -inside- the trap. I scattered all the flies outside and reset the trap beside the (now clean) reptile tank. The next morning, all the fruit-flies in that area were also inside the trap. The dark-eyed fruit-flies (of whichever species I have here; D. repleta, D. hydei, or D. robusta) really, really, love the fruit of the "Pumpkin Tree" plant.

I've dehydrated and powdered the remaining fruit to save them for later use as a bait. If the dark-eyed fruit-flies ever reappear, I'll mix some of the powder with some water as bait and continue the experiment. I could also do some experiments outside next summer, as the dark-eyed fruit flies are likely to prosper in my compost pile again.

I've saved seeds from the "Pumpkin Tree" plant and will definitely be growing it again for its decorative and fly-trapping features.