Friday, October 26, 2012

An unwelcome kiss

Adult kissing bugs are 1/2 to 1 inch-long, dark in color with
reddish to yellow bands on the edges of the abdomen, and
a cone-shaped head.  They are common throughout Texas
(and many other states), especially in southern parts of the state.
Their natural hosts include wild rodents.
One of the potentially more serious, yet poorly recognized, indoor biting insects in Texas is the cone-nosed bug, or kissing bug, Triatoma species.

Kissing bugs are so-called because of their habit of biting people (and other animals) at night, often around the face or lips.  The bite can be extremely itchy.  The worst part, however, is that there is a relatively small risk (in the U.S.) that these bugs could transmit a parasite-caused disease called Chagas.

I have blogged previously about kissing bugs and Chagas disease, and have advised that there really was no place to report these bugs to, or any place to have them sent for testing.  That's changed recently, however, thanks to a Texas Department of State Health Services (TDSHS) website and new DNA diagnostic tests for the pathogen.

The new website and testing service is available online. The site allows any Texas resident to send Triatome (kissing) bugs in for identification and analysis for the Chagas parasite at no charge.  Preference in testing will be given to bugs that have been documented as feeding on people.  There are limited resources for testing bugs collected as a curiosity, so those submissions may not be tested for months, or ever.

There is a downside to this new service, though.  Just because a Triatome bug collected from a home turns out to be carrying the Trypanosome (Chagas) parasite does not mean that people in the infested home are at high risk of the disease.  The low rate of Chagas disease in Texas suggests that the kissing bugs in Texas are not very good at transmitting the disease--at least to people (dogs are another story).  That's good news. The bad news is that it may be difficult to convince your customers that having inch-long, disease-infested, blood sucking bugs in their home is nothing to worry about.

In any case, should you catch one or more of these insects in a customer's home, it's good to know that there is some place you can turn for more information.  Thanks to Wizzie Brown for alerting us to the availability of this new resource.

Wednesday, October 3, 2012

Crazy ant name gets crazy

A closeup of Nylanderia pubens and the male
genitalia (bottom) of N. fulva (left) and pubens.
Based on the recent paper, invasive crazy
ants found in the southern U.S. in recent years are
thought to be N. pubens, with the proposed
common name, tawny crazy ant. Photo from Gotzek
et al. 2012.
One of the most impressive new structural insect pests to emerge in the southern U.S. over the past few years (besides the bed bug) is a new ant, called variously, the Rasberry crazy ant, the Caribbean crazy ant, and the hairy crazy ant.  According to Texas A&M University graduate student Danny McDonald, this ant finally has a definitive name... well at least a definitive scientific name.  

Dietrich Gotzek and colleagues from the Smithsonian Institute and Towson University in Maryland (2012, PLoS ONE 7(9): e45314), examined ants from Texas, Louisiana, Mississippi and Florida, and concluded that the ant we know in Texas as the Rasberry crazy ant is not a new species, but a previously described ant from South America, Nylanderia fulva.  Their conclusion is based on statistical analysis of numerous body part characters (morphometric analysis), DNA comparisons, and comparison of the shape and condition of the male ant's genitals. The researchers report that there is no reliable way to distinguish N. fulva workers from the worker ants of the closely related, so called "Caribbean crazy ant", N. pubens.  The Caribbean crazy ant is the species that at one time was thought to be, or be the closest thing to, the Rasberry crazy ant in Texas.  I'm no expert on the techniques used in these studies, but based on the agreement between three independent methods of settling the question, and Danny McDonald's seal of approval, the matter appears to me to be definitively settled.  

So what is Nylanderia fulva, and what do we know about it?  This ant, which has never been given an English common name, is from South America--probably from the southern part of the continent according to the study's authors.  It was first described from Brazil, but major population explosions of this ant are thought to have occurred in Columbia, S.A. as well as Bermuda, the St. Croix Islands, and possibly southern Florida. One of the characteristics of this ant that distinguish it from its Caribbean cousin, N. pubens, is its ability to develop high populations and become a serious pest.

The Controversy

If entomologists have settled happily on a scientific name for this ant, it's hard to find anyone who is happy about the common name for this ant. So what exactly is a common name and why is it so controversial? Most insect common names have probably come from the general, non-science public. The problem with common names is that frequently people from different social circles, or language groups, or regions have given different common names for the same insect. Also, the same common name may refer to different organisms.  Of course this drives the obsessive-compulsive scientific community absolutely batty. 

Since 1903 professional entomologists have attempted to bring some order to common names of insects via rules and an approval committee and a formal list of acceptable common names.  The Entomological Society of America (ESA) currently maintains a list of approved common names.  This makes entomologists happy, but can rub some people the wrong way, especially those who get attached to a favored common name or spelling (e.g., the media who want to write "bedbug" instead of bed bug).  

Such is the case, for some, with Nylanderia fulva. The authors of the paper have recommended that the ant should be called the tawny crazy ant, because of its light brown color. But this so-called common name is anything but in common use. At least three common names have been applied to this ant since recent reports of it in the U.S.  In Florida it has been referred to as the Caribbean crazy ant (a mis-identification, now cleared up by Gotzek's paper).  In Louisiana it has been referred to as the hairy crazy ant.  And of course the pest control industry in Texas has known it for the past 10 years as the Rasberry crazy ant, in honor of Tom Rasberry, the sharp-eyed PMP who first brought it to the attention of Texas A&M researchers and many others.  

Friends of Rasberry argue that the name Rasberry crazy ant should be the official name because it has been in general use the longest and it honors the person that pointed it out (at least in Texas) to professional entomologists.  Others don't especially like the common name because it's confusing to people who don't know Rasberry's story, or who think its an ant pest found on berry crops. Others don't accept the Rasberry name because it arose locally, and has no meaning to folks in other areas who have known about the ant for many years in say, Florida or Mississippi or Bermuda. 

I'm mostly happy to stay out of the controversy and wait until the dust settles; but I will likely use whatever name the ESA settles on. Scientists, after all, have been the originators of many of the common names in use today.  At the same time I sympathize with those who object to entomologists (who generally dislike common names in the first place) choosing a fusty, and rather nondescript name. This may be one of the reasons the botanist de Candolle, writing in 1868, said, 
"Every friend of science ought to be opposed to the introduction into a modern language of names of plants that are not already there, unless they are derived from a Latin botanical name that has undergone but a slight alteration."
Some Useful Links

To learn more about why Nylanderia fulva is such a pest, see the Texas A&M University website on this insect.  Also, Alex Wild has created a useful and beautiful set of directions on how to identify N. fulva. The photos from this site will give you a better appreciation of the fine distinctions and types of characters used to distinguish ants at the species level.