0349. Ecology and Diversity of Cockroaches (Dictyoptera: Blattaria) from the Virgin Islands.

Abstract

The Virgin Islands (except St. Croix) are geologically part of the Puerto Rico Bank and biologically related to Puerto Rico, but their cockroaches (Dictyoptera: Blattaria) were not yet as well studied as those on Puerto Rico. To elucidate the number of species, life history, range distribution, and seasonal abundance of these cockroaches, we have conducted a quantitative study since June 2000 using a Malaise trap on Guana Island, British Virgin Islands, in addition to other conventional collecting methods. We found 21 species: Blattella germanica (Linnaeus), Cariblatta antiguensis (Saussure and Zehntner), Cariblatta sp. 2, Cariblatta sp. 3, Colapteroblatta sp. 1, Eurycotis improcera Rehn, Eurycotis sp. 2, Euthlastoblatta facies (Walker), Hemiblabera brunneri (Saussure), Nyctibora lutzi Rehn and Hebard, Panchlora sagax Rehn and Hebard, Periplaneta americana (Linnaeus), P. australasiae (Fabricius), Plectoptera infulata Rehn and Hebard, P. rhabdota Rehn and Hebard, Plectoptera sp. 3, Pycnoscelus surinamensis (Linnaeus), Symploce pararufi collis Roth, S. rufi collis (Fabricius), polyphagid sp. 1 (Compsodes sp. 1), and polyphagid sp. 2. Among them, nine are new records for the Virgin Islands and fi ve for Guana Island. In addition, Euthlastoblatta diaphana (Fabricius), Nyctibora noctivaga Rehn, Panchlora nivea (Linnaeus), P. viridis (Fabricius), and Rhyparobia maderae (Fabricius) were recorded historically but were not rediscovered. As a result, the number of species is increased from 17 to 26 for the Virgin Islands, and from 10 to 15 for Guana Island. Overall, only fi ve species are edifi carian and likely introduced. Nymphs of polyphagid sp. 2 and Euthlastoblatta facies are reported for the fi rst time as dwellers in termite runways. Only eight species came to the Malaise trap; their phenology illustrates close but not necessarily synchronic relationship with both the timing and amount of rainfall. Monthly abundance showed spring and fall highs and summer and winter lows. Yearly abundance reached lows when annual rainfall decreased below a threshold average of 2.0 mm per day. Seasonality and response to drought varied among species. This paper lays a foundation for further research on diversity of cockroaches from the Virgin Islands and their relationships with those from Puerto Rico.