Paralabellula dorsalis (Burmeister, 1838)

Kamimura, Yoshitaka & Ferreira, Rodrigo L., 2017, Earwigs from Brazilian caves, with notes on the taxonomic and nomenclatural problems of the Dermaptera (Insecta), ZooKeys 713, pp. 25-52 : 36-39

Paralabellula dorsalis (Burmeister, 1838) Figs 36-42

Material examined.

2 ♂♂, 9 ♀♀, 8 nymphs, Cave N 5SM2-099 (= GEM-1799 cave), Parauapebas , Pará, 5.v.2011, CARSTE leg. ( ISLA 15563) - 1 ♀, Cave N 5SM2-019 (= GEM-1739 cave), Parauapebas, Pará, 31.x.2010, CARSTE leg. ( ISLA 15562) - 3♀, Cave N 5SM2-099 (= GEM-1799 cave), Parauapebas, Pará, 31.x.2010, CARSTE leg. ( ISLA 15560) - 1 ♂, 2 ♀♀, 8 nymphs, Cave N 5SM2-019 (= GEM-1739 cave), Parauapebas, Pará, 5.v.2011, CARSTE leg. ( ISLA 15561) - 1 nymph, Cave N 5SM2-019 (= GEM-1739 cave), Parauapebas, Pará, 31.x.2010, CARSTE leg. ( ISLA 21084) - 1 nymph, Cave N 5SM2-019 (= GEM-1739 cave), Parauapebas, Pará, 5.v.2011, CARSTE leg. ( ISLA 21089) - 1 nymph, Cave N 5SM2-019 (= GEM-1739 cave), Parauapebas, Pará, 5.v.2011, CARSTE leg. ( ISLA 21090) - 3 nymphs, Cave N 5SM2-019 (= GEM-1739 cave), Parauapebas, Pará, 31.x.2010, CARSTE leg. ( ISLA 21094) .

Association with caves.

Many specimens of P. dorsalis were found in two iron ore caves (N5SM2-019 cave - synonym of GEM-1739 cave, and N5SM2-099 cave - synonym of GEM-1799 cave), both located in Carajás region ( Pará state). These caves occur in an iron ore plateau surrounded by the Amazon forest. However, they are in an area of metallophilic savannah, a vegetation type usually found at the top of plateaus. The caves are considerably large (> 100 m in horizontal projection) compared to other caves in the area. Although many caves were sampled in the plateau (at least 100 caves), this species was found in only these two caves, which contain huge colonies of the insectivorous bat genus Pteronotus ( Pteronotus gymnonotus Wagner, 1843, in the N5SM2-019 cave and Pteronotus parnellii (Gray, 1843) in the N5SM2-099 cave). These colonies produce large guano piles, where several individuals of P. dorsalis were observed. The populations of P. dorsalis , which include both adults and nymphs, were observed in both dry and rainy seasons in the two caves, strongly suggesting that they are troglophilic.

Description and remarks.

The external morphologies and genital structures of male and female specimens were examined (Figs 36-41 ) and matched those of Paralabellula dorsalis ( Burmeister 1838; Brunner 1906; Brindle 1971a, b, c; Steinmann 1989a; Briceño 1997; Eberhard et al. 1998). Winged and wingless morphs have been reported for a Costa Rican population of this species, where wingless individuals always predominated in the wild ( Briceño and Eberhard 1987). Significantly more winged adults emerged when nymphs were subjected to low nutritional conditions ( Briceño and Eberhard 1987). All adults (3 males and 13 females) examined in this study were winged morphs with fully developed tegmina and hind wings (Figs 36 , 39 ). These findings may have been due to the poor nutritional conditions in caves. Although previous authors noted that each branch of the male forceps has a small inner tooth at the base (see Brindle 1971a, b, c; Sakai 1993), all males (n = 3) examined in this study lacked this tooth (Fig. 37 ). However, one male specimen from Moniquira, Colombia, determined by A. Brindle, also lacked a tooth at the base of the forceps (Fig. 42 ).

Based on samples collected from Costa Rica, Briceño (1997) reported the detailed genital structures of this species, which included a horn-like structure and several heavily sclerotized toothed plates in the penis lobe. These structures were also found in the three male samples examined in this study (ho and tp, respectively, in Fig. 38 ). The spermatheca of this species is a long, thin, blind duct lacking a capsule at the distal end ( Mariani 1994; Briceño 1997). Briceño (1997) also reported the presence of multiple fine spines around the spermathecal opening. All such features were present in the specimens examined in this study (Fig. 40 , 41 ).

Using specimens fixed during copulation, Briceño (1997) also examined coupling of the male and female genitalia. Toothed plates were exposed by eversion of the inflated penis lobe, and contacted the inner walls of the vagina, including the spiny area. The horn-like structure functioned as a guiding sheath for the virga, potentially to facilitate insertion into the female spermatheca. There is accumulating evidence that many male animals inflict wounds on the female during mating through use of their genital structures ( Lange et al. 2013; Tatarnic et al. 2014; Reinhardt et al. 2014). However, this mode of mating, termed traumatic mating, has been reported in only two species of earwigs, Echinosoma denticulatum Hincks, 1959 ( Pygidicranidae : Echinosomatinae ; Kamimura and Lee 2014a) and Marava arachidis (Yersin, 1860) ( Spongiphoridae : Spongiphorinae ; Kamimura et al. 2016b). While Briceño (1997) failed to mention the occurrence of copulatory wounding in P. dorsalis , melanized patches on the membranous region at the spermathecal opening were observed in this study (n = 2; Figs 40 , 41 ). This finding suggests that the male genitalia cause wounding during copulation.

Distribution.

West Indies, Mexico, Costa Rica, Panama and northern South America (including Brazil).

Figures

Figures 36 - 45. 36 - 38 Paralabellula dorsalis (male): habitus (36), forceps (dorsolateral view) (37), and genitalia (38) 39 - 41 Paralabellula dorsalis (female): habitus (39), spermatheca and spiny area in the genitalia (40, 41). Repaired wound patches are indicated by the red arrowheads in Figs 40 and 41 42 Paralabellula dorsalis (male; a specimen from Colombia, det. A. Brindle; OMHH S. Sakai Collection, 31. iii. 2002 [01 - 25]): abdomen and forceps (dorsolateral view) 43 - 44 Doru luteipes (female): habitus (43), and spermatheca (44) 45 Doru lineare (female; coll. Y. Kamimura, at Varzelandia, Minas Gerais, Brazil, outside of caves on 13. iii. 2016): spermatheca. Scale bars 3 mm for Figs 36, 39, 42, 43; 0.5 mm for 37; 200 μm for Figs 38, 40, 41, 44, 45.