The New Neotropical Companion

Anyone visiting the Neotropics should be aware of the

animals that have the potential to annoy you or even

endanger you. I have discussed snakes in chapter 16, but

it is time to talk a bit about some of the small invertebrates

that you will likely meet— and likely dislike.

Mosquitoes

Mosquitoes are ubiquitous in the Torrid Zone, and there

are hordes of them in the temperate and polar zones

as well. They have done really well since they evolved.

You might be surprised by how few mosquitoes you

encounter on a visit to the Neotropics. But then again,

you might find a lot. Mosquito abundance depends

partly on season. During the dry season there are fewer

mosquitoes; during rainy season, they tend to peak.

Mosquitoes are irritating and produce itchy bites,

but more serious potential problems are associated

with them. The mosquitoes in the genus Anopheles

are well- known vectors of the various Plasmodium

species (a kind of protozoan) that cause malaria.

Other mosquitoes are vectors for yellow fever and

dengue fever. The 2015 outbreak of Zika virus in Brazil

has been linked to Aedes mosquitoes as vectors. Any

visitor to the Neotropics should become familiar with

the risks of mosquito- borne diseases in the region in

which travel is planned (see the “Travelers’ Health”

section of the Centers for Disease Control website:

http://wwwnc.cdc.gov/travel) and consult with a

physician about appropriate preventative medications.

Some countries require certification of yellow fever

vaccination as a requirement for entrance.

It is advisable to use insect repellent when visiting

mosquito habitats and to be diligent about avoiding

mosquito bites. Dress accordingly. The more of you that

is exposed, the more chance there is that a mosquito will

dine on your blood. Mosquitoes are active at all times

but are most active at dawn, dusk, and during the night.

Chiggers and Ticks

Everyone who visits the tropics eventually will talk

about chiggers, which, like ticks, are in the class

Arachnida, along with spiders and scorpions. And

many humans will serve, quite unwillingly, as ground

zero for a host of chiggers. Chiggers are actually larval

mites of the family Trombiculidae, and they come

in droves. You don’t see them on you because they

are virtually microscopic. Instead, you see the little

red spots they produce and you feel intense itching.

Chiggers occur in forests but are far more numerous in

sunny, grassy areas, including lawns. Chiggers clamber

onto your body, go exploring, and tend to accumulate

around areas on your person where garments have

elastic bands or compress against you, such as tops of

socks and underwear. They do not burrow into you

but they do inject their teensy mouthparts into the

skin and begin devouring it. That is what produces the

itching reaction. Once that reaction begins, it continues

regardless of whether you scratch or not (and you will

want to scratch). There is little to do at that point but

use standard anti- itch medication, such as over- the-

counter Benadryl. The good news, such as it is, is that

you can significantly reduce your exposure to chiggers

(and ticks) by tucking your pant legs tightly into your

socks (which looks geeky but sort of works) and, better

yet, whack your ankles, shoes, and lower extremities

with a sock containing sulfur powder, reputed to repel

chiggers. Most field stations have such socks readily

available and encourage their usage. And it works.

Ticks act sort of like grown- up chiggers (they’re

not really similar, as chiggers are mites). But they are

potentially more dangerous, as there are numerous

tick- borne illnesses in the world. So be careful of ticks

and follow the advice to check yourself for ticks. Dry

season seems to be the time ticks are most numerous.

My group enjoyed a walk in a Brazilian várzea forest

during dry season, but many of us emerged with dozens

of tiny ticks the size of pinheads marching from ankle

upward. When that occurs, get in the shower and, if

possible, consider allopreening with a fellow human.

Botflies

A fly is a fly is a fly. Well, not really. Some flies are

best avoided. The ones that come around your peanut

butter and jelly sandwich are likely harmless. But some

that you encounter (even indirectly) in the field are

not. Some are biting flies, related to the horse flies and

deer flies that are familiar to most people. These are

annoying but not dangerous.

And then there is another group, the botflies, which

offer another solid reason you should avoid mosquitoes.

Appendix. Words of Caution: Be Sure to Read This

chapter 18 appendix 389