Flight Phenology of Two Coptotermes Species (Isoptera: Rhinotermitidae) in Southeastern Florida.

The dispersal flight activity ("swarming") of two invasive subterranean termite species, Coptotermes gestroi (Wasmann) and Coptotermes formosanus Shiraki, was monitored in metropolitan southeastern Florida, where both species are now sympatric and major structural pests. Historical records of alates collected in the area showed that the two species have distinct peaks of flight activity, from mid-February to late April for C. gestroi, and from early April to late June for C. formosanus. However, an overlap of the two dispersal flight seasons has been observed since at least 2005. The daily monitoring of dispersal flight events in southeastern Florida in 2014, 2015, and 2016 confirmed that simultaneous flights occurred several times each year. In addition, environmental conditions for favorable flights were identified, and it was established that low temperature was the primary factor inhibiting both species from dispersal flights, while all other factors had little impact on the occurrence of major dispersal flight events. However, both species shared similar temperature requirements for favorable dispersal flight conditions despite distinct peaks of activity over time. The analysis of sex ratios and average weights of the alates suggests that intrinsic colony factors are important for the timing of the maturation of alates, and that once a cohort of individuals is ready to disperse, a flight may occur as soon as the environmental conditions are favorable.

Reinvasion Dynamics of Subterranean Termites (Isoptera: Rhinotermitidae) Following the Elimination of All Detectable Colonies in a Large Area.

Following the elimination of all detectable termite colonies in the 32-acre Louis Armstrong Park in New Orleans, LA, in 2002­2003, termite activity was monitored by using 808 Sentricon stations. Between January 2004 and July 2005, termites were found in 8­11 stations. In August 2005, the Park was flooded by Hurricane Katrina, but termites remained active. Post-Katrina termite activity levels of 16­21 stations were recorded throughout 2006, and in October 2007, the activity drastically increased to 43 stations. This rapid increase of termite activity continued into 2008, and a total of 94 stations harbored termite activities by July 2008. Termite activity peaked at 109 stations in September 2008 and then leveled down to 64 stations in March 2009. Termite activity in the Park between 2004 and 2009 was described by a Sigmoid model with a carrying capacity of 76 stations, and a Sigmoid mid-point of 1,202 d. In April 2009, a total of 14 colonies of Coptotermes formosanus Shiraki and one colony of Reticulitermes flavipes (Kollar) were delineated by using microsatellite genotyping and mark­recapture protocol. Of the 15 colonies, eight near the Park border probably originated from existing colonies from outside, and seven C. formosanus colonies found inside the Park were probably initiated by alate pairs. Our results showed that, if surrounded by high population pressure of termites and no control measures are applied, an area cleared of termite populations by baits can be completely re-populated by termites from outside in 53 mo.

Dispersal Flights of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae).

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a pest of major economic concern. This termite is particularly known for its tendency to establish populations in nonendemic areas via maritime vessels as well as human-aided transport of infested materials. The natural spread of this species after new introductions occurs in part by dispersal flights originating from mature colonies. Dispersal flight activity is also the primary variable for the evaluation of area-wide management programs. Few studies exist describing the dynamics and distribution of a typical dispersal flight for this species. The present study used data collected by mark-recapture of C. formosanus alates over 12 individual evenings of dispersal flights in the New Orleans French Quarter. In this study, we found that for one selected flight dispersal location, which was not affected by a high density of trap locations nearby, alates flew on average 621 m from their parent colony. A new record of a 1,300-m dispersal flight was recorded. Spatial analysis showed that neither wind nor light affected the direction of flight, which may, however, be attributed to scarce light and wind measurements in the study region.

Reinvasion and colony expansion of Coptotermes formosanus (Isoptera: Rhinotermitidae) after areawide elimination.

The population recovery of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) colonies were monitored after an areawide elimination of all detectable colonies from September 2003 to August 2005 in Louis Armstrong Park, New Orleans, LA. Six colonies reinvaded the vacant niche created by the full elimination. These colonies expanded their territories throughout the study period. This represented 43% of the original number of colonies present in the park before the elimination. To determine the mode of the reinvasion, nuptial pair establishment was monitored during the C. formosanus dispersal flight seasons. Nuptial pairs were discovered up to 1 yr after the elimination. Morphological and genetic data were collected from field colonies before the full elimination in 2002 and again in 2005 after the reinvasion of these territories by new colonies. These data were used to estimate the relative age of reinvading colonies as compared with their predecessors. It is proposed that the first three reinvading colonies detected were smaller colonies that were undetectable before the full elimination, or were older, established colonies present outside of the park, that expanded their foraging territories into the park in the absence of competition from the eliminated populations. The subsequent three colonies to reinvade seemed to be small colonies founded during or just before the study period by an imago pair after a dispersal flight into the park from outlying areas. The implications of this study on subterranean termite areawide integrated pest management strategies are discussed.