Scapteriscus campaniformia

Kostromytska, Olga, Scharf, Michael E. & Buss, Eileen A., 2015, Types and functions of mole cricket (Orthoptera: Gryllotalpidae) antennal and palpal sensilla, Florida Entomologist 98 (2), pp. 593-605 : 599

S. campaniformia

These sensilla were on the palps and nearly every flagellomere. They had a round or ovoid central area (cap of the sensilla) encircled by a cuticular ring. The dimensions of s. campaniformia of the antennae were on average 3 and 6 μm for the inner and outer circles, respectively ( Fig. 8 C, D ). Their dimensions ranged from 9 × 16 μm to 5 × 65 μm. This type of sensilla was present on various parts of the insect body and occurred on each mole cricket species examined.

TYPES, ABUNDANCE AND DISTRIBUTION OF SENSILLA ON MOLE CRICKET MAXILLARY AND LABIAL PALPS

The tips of the maxillary and labial palps were weakly sclerotized, with a distinct sensillar field of about 0.35 mm ², which was densely covered with sensilla of different types and functions ( Fig. 9A ). About 0.2 sensilla were found per μm² on the palps. Most of the observed sensilla on maxillary and labial palps matched the description of s. chaetica ( Keil 1999) , which are usually associated with mechanoreception and contact chemoreception ( Fig. 9 B ). SEM inspection indicated that they had slits/grooves at least on one side, which suggested they might be multifunctional. Other sensilla on the maxillary and labial palps were s. coeloconica with tip pores ( Fig. 9 C, D ), tip-pore sensilla ( Fig. 9 E ), and club-like s. basioconica ( Fig. 9 F ).

DIFFERENCES IN SENSILLA TYPES, SIZES, ABUNDANCE AND DISTRIBUTION AMONG MOLE CRICKET SPECIES, SEXES AND LIFE STAGES

The numbers of s. chaetica (I, II and III types combined) and s. basioconica varied depending on mole cricket species, sex and location on the antennae. On average, S. borellii and S. abbreviatus had more s. chaetica compared to S. vicinus (F = 17.5; df = 1, 567; P <0.001). The middle part of the antennae had more s. chaetica (F = 95; df = 3, 567; P <0.001) and s. basioconica (F = 60.4; df = 3, 567; P <0.001) than the distal and basal parts. Sensilla were more abundant on female antennae (F = 51.2; df = 1, 567; P <0.001) than on male antennae for all species.

All described types of sensilla were found on the nymphal antennae, and the 3 Scapteriscus species doubled the number of segments and sensilla per segment during their development. On average, S. abbreviatus had more s. chaetica per flagellomere than S. vicinus (F = 97.9; df = 1, 559; P <0.001). Scapteriscus abbreviatus had the most s. basioconica and S. borellii had the fewest of these sensilla among the 3 species (F = 92.7; df = 1, 559; P <0.001).

Figures

Fig. 8. Antennal s. coeloconicum (type I), located in the cuticular pit (×28k) (A), in contrast to s. ceoloconicum (×25k) (type II) positioned on the antennal surface (B). S. campaniformia, proprioreceptor, can be located on the tip of the segment (× 17k) (C) and at the midsection (× 21k) (D).

Fig. 9. Mole cricket labial and maxillary palps are densely covered with sensilla (× 300) (A). The dominant type is s. chaetica (× 8k) (B), other types include s. coeloconica (×15k) (C) with tip-pore (× 40k) (D), single-wall tip-pore sensilla (× 9k) (E) and club-like s. basioconica (× 11k) (F).