Symploce, Hebard, 1916

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 : 21

20. Symploce ru fi collis (Fabricius) ( Fig. 16 )

Blatta ruficollis Fabricius 1787: 226 ; “India.” USVI: St. Thomas Island (lectotype by Princis 1949: 362) .

Diagnosis. Adults 12–14 mm, with full tegmina in both sexes; elongate oval, reddish brown with legs and venter lighter; venter with 1 lateral pair of black spots on each sternite, plus 1 and 3–4 dorsal black spots on each forecoxa, mesocoxa, and metacoxa, respectively.

Comments. Symploce ruficollis has the entire leg reddish in contrast to its congener S. pararuficollis (Species 19) who has contrasting black tibiae. It is probably arboreal and nocturnal; adult individuals were active on vegetation at night and never under ground cover ( Table 1). The sex ratio is about 1:1. It is not as frequently seen or numerous as S. pararuficollis ( Tables 2–3). Though a relatively common species on Guana Island, we collected few nymphs to distinguish S. ruficollis from the congener other than the tibia color.

The abundance pattern showed a spring high. This is the only species caught frequently in the Malaise trap, whose monthly abundance synchronized closely with the spring rainfall peak ( Table 2); notably the abundance increase did not lag behind the spring rainfall peak. Abundance was particularly high in June 2000 (20 individuals), followed by May 2005, April and October 2008, and March-April 2011 ( Fig. 3 , Table 3). A spike of 15.8 mm heavy rainfall in November 2003 did not seem to impact abundance ( Fig. 3 ).

Roth (1994) first recorded this species from Guana Island; it is herein recorded for the first time on Anegada, Great Camanoe, Jost Van Dyke, Little Thatch, Moskito, Tortola, and Virgin Gorda of BVI, in addition to other previous records on Guana and Necker of BVI, St. John and St. Thomas of USVI, Culebra Island, and Puerto Rico ( Princis 1969, Roth 1994, Gutiérrez and Fisk 1998, Lazell 2005).

Specimens examined. BDVC — 1 male / 1 female, BVI, Anegada Is. , 26/ 27.X.2009, W. Lu & S. Valentine-Cooper ; 2 females, BVI, Great Camanoe Is. , 20.X.2008, Lu & S. C. Valentine-Cooper ; 19 males, BVI, Guana Is., III, IX-X, at UV, Malaise trap ; 27 females, BVI, Guana Is., I, IX-X, at UV, Malaise trap ; 3 adults, BVI, Little Thatch Is. , 11.X.2010, E. Wright ; 2 males, BVI, Moskito Is. , 25.X.2007, W. Lu, sweep ; 1 female, BVI, Moskito Is. , 23.X.2008, Valentine-Cooper & Lu ; 1 male, BVI, Necker Is. , 2-5. VI.2005, W. Lu ; 3 adults, BVI, Necker Is. , 16.X.2010, W. Lu. MCZ — 10 adults, USVI, St. John, Great Cruz Bay, 15-23. VI.1996, B. & B. Valentine ; 10 adults, BVI, Guana Is., B. & B. Valentine. NMNH — 3 adults, BVI, Anegada Is .; 4 adults, BVI, Jost Van Dyke Is .; 4 adults, BVI, Tortola Is .; 20 adults, BVI, Virgin Gorda Is. UDCC — 1 adult, BVI, Guana Is. , 23.X.1997, C. R. Bartlett. VIIS — 2 adults, USVI, St. John Is., Lameshur Bay, 18-27. VII.1972, A. Gray ; 1 male; USVI, St. John Is. , Lameshur Ranger Station, 23XI.1958, C. F. Adams .

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).