Bothynus striatellus (Fairmaire, 1878)

de Jesus, Waner Pereira, Martins, Gabriella Torres & Rodrigues, Sérgio Roberto, 2024, Identification and Description of Antennal Sensilla of Bothynus medon (Germar) and Bothynus striatellus (Fairmaire) (Coleoptera: Scarabaeidae), The Coleopterists Bulletin 78 (2), pp. 273-280 : 277

BOTHYNUS STRIATELLUS

Females of B. striatellus had an average body length of 19.57 ± 0.78 mm, while males had an average length of 18.66 ± 0.81 mm, with no significant difference between the sexes (t = 2.03; df = 11; P <0.06). The average body width for females was 11.28 ± 0.48 mm, whereas for males it was 11.00 ± 0.63 mm, again with no significant difference between the sexes (t = 0.91; df = 11; P <0.3).

Regarding the proximal lamellae, no significant differences in length (t = 0.42; df = 6; P <0.68) or width (t = 0.17; df = 6; P <0.8) were found between females and males.However, for the medial lamellae, significant differences in both length (t = 5.01; df = 6; P <0.0024) and width (t = 3.02; df = 6; P <0.02) were noted between females and males, with females having longer and wider lamellae. For the distal lamellae, no significant differences in length (t = 1.33; df = 6; P <0.22) or width (t = 1.47; df = 6; P <0.19) were observed between the sexes ( Table 3).

In the proximal lamella of females (n = 4), 59 trichoid sensilla and 47 chaetic sensilla were quantified, while in males (n = 4), 42 trichoid sensilla and 48 chaetic sensilla were quantified. Greater numbers of placoid and coeloconic sensilla were observed on the lamellae of male B. striatellus , with significant differences compared to females (t = 16.26; df = 10; P <0.001) and (t = 11.08; df = 10; P <0.001), respectively. Conversely, basiconic sensilla were found in higher quantities in females, with significant differences compared to males (t = 2.94; df = 10; P <0.001). For the total number of sensilla, greater numbers were found in males, with significant differences between females and males (t = 16.45; df = 10; P <0.001) ( Table 4).

Type I placoid sensilla have an average diameter of 9.26 μm (6.6‒14.0 μm, n = 20). Type II placoid sensilla have an average diameter of 9.13 μm (6.6‒13.3 μm, n = 20), while type III placoid sensilla have an average diameter of 13.87 μm (9.6‒20.0 μm, n = 20) .

In the lamellae of females, a total of 17,452 sensilla were counted, of which 17,253 (98.86%) were placoid, 174 (1.00%) were coeloconic, and 25 (0.14%) were basiconic ( Table 4). In the lamellae of males, a total of 19,480 sensilla were counted, of which 19,211 (98.62%) were placoid, 251 (1.29%) were coeloconic, and 18 (0.09%) were basiconic ( Table 4).