Symploce pararu

Lu, Wenhua, Valentine, Barry D., Perez-Gelabert, Daniel E. & Gutiérrez, Esteban, 2014, Ecology and Diversity of Cockroaches (Dictyoptera: Blattaria) from the Virgin Islands, Insecta Mundi 2014 (349), pp. 1-32 : 20-21

19. Symploce pararu fi collis Roth ( Fig. 15 )

Symploce pararuficollis Roth 1994: 45 ; BVI: Guana Island.

Diagnosis. Adults 15–19 mm, elongate oval, with full tegmina in both sexes; reddish brown with tibiae dark brown to black in contrast to pale reddish femora; underside lighter, with 1 (rarely 2) lateral pair of black spots on each sternite, plus 1 ventral and 2–3 dorsal black spots on each coxa.

Comments. Symploce pararuficollis is the second species originally described from the Virgin Islands on the Greater Puerto Rico Bank. The black tibia distinguishes it from the following congener. It is probably arboreal and nocturnal; individuals were active on vegetation and never under ground cover at night ( Table 1). The sex ratio is about 1:1. This is the most commonly seen and most numerous species on Guana Island. However, we collected few nymphs to distinguish S. pararuficollis from the congener (Species 20) other than the black tibiae. The nymphs are ground dwellers of leaf litter and probably diurnal because they were actively escaping from us when disturbed during the day. Surprisingly, the nymphs have not been found in the forest edge Malaise trap, suggesting that they are very much terrestrial and do not behaviorally climb, unlike their arboreal adults.

The abundance pattern showed two highs; the fall increase topped the spring increase, unlike other species frequently captured in the forest edge Malaise trap ( Table 2). Abundance was particularly high in June 2000 (209 individuals), followed by November 2004 and December 2007 ( Fig. 3 , Table 3). In these three cases, annual rainfall was 1.7, 2.8, and 1.6 mm with that of prior three years averaging above 3.1, 2.6, and 2.6 mm, respectively. The annual rainfall was 3.5 mm with a spike of 15.8 mm in November 2003; it did not induce a striking abundance increase like that in 2000, but may have contributed to a delayed and sharp abundance increase in 2004.

Roth (1994) first described this species from Guana Island; it is herein recorded for the first time on St. John of USVI, Anegada, Great Camanoe, Little Thatch, Moskito, and Tortola of BVI, in addition to a previous record on Puerto Rico ( Gutiérrez and Fisk 1998, Gutiérrez 1999a). We have not found it on Necker, even though it occurs on Anegada, the easternmost island on the Puerto Rico Bank.

Specimens examined. BDVC — 1 male, BVI, Anegada Is. , 26/ 27.X.2009, W. Lu & S. Valentine-Cooper ; 1 male / 1female, BVI, Great Camanoe Is. , 20.X.2008, Lu & S. C. Valentine-Cooper, at night ; 20 females, BVI, Guana Is., I, III, IX-X, at UV, Malaise trap ; 17 males, BVI, Guana Is., I, II, VIII-IX, Malaise trap ; 1 adult, BVI, Little Thatch Is. , 11.X.2010, E. Wright ; 1 adult, BVI, Little Thatch Is. , 11-12.X.2010, S. C. Valentine-Cooper ; 1 nymph, BVI, Moskito Is. , 23.X.2012, E. Hill ; 1 female, BVI, Tortola Is. , Chalwell, XI.2002, C. Petrovic, at light ; 2 females, BVI, Tortola Is. , Chalwell, XII.2009, C. Petrovic, Malaise trap. MCZ — 6 adults, BVI, Guana Is., B. & B. Valentine ; 5 adults, USVI, St. John , Great Cruz Bay , 15-23. VI.1996, B. & B. Valentine. UDCC — 4 adults, BVI, Guana Is. , 10.X.1994, 23/ 26.X.1997, C. R. Bartlett. VIIS — 2 adults, USVI, St. John Is., Lameshur Bay, 18-27. VII.1972, A. Gray ; 1 female, USVI, St. John Is., Trunk Bay, BS ; 1 male, USVI, St. John Is. , 26.I.1970 .

Figures

Figure 3. Relationship of average rainfall (mm) with monthly abundance in number of individuals of five cockroach species frequently captured in a Malaise trap within a forest edge from June 2000 through October 2011 on Guana Island, British Virgin Islands (missing 4 samples of VII/IX.2004, IV.2005, and VII.2007).

Figures 13–16. Blattellidae. 13) Plectoptera infulata adult from Tortola Island. 14) Plectoptera rhabdota adult from Guana Island. 15) Symploce pararuficollis adult from Guana Island. 16) Symploce ruficollis adult from Guana Island (all specimens in BDVC).