Erotylina jaspidea (Erichson, 1847)

Xavier, Miguel Dorcino, Pecci-Maddalena, Italo Salvatore De Castro, Lopes-Andrade, Cristiano & Baseia, Iuri Goulart, 2022, Life History of Erotylina jaspidea (Erichson, 1847) (Coleoptera, Erotyloidea Erotylidae, Erotylini), Zootaxa 5182 (5), pp. 489-498 : 492-493

Erotylina jaspidea (Erichson, 1847)

Figs 1–12

Immature stages. Eggs. 2.4 mm long and 0.96 mm wide (n=1) oval, elongate, cylindrical; yellowish to whitish. Chorion lacking surface sculpturing; larval mandibles and tarsi visible just before eclosion ( Fig. 2 ). Larvae. With the general appearance of other Erotylini (see examples in Costa et al. 1988). Fourth instar larvae: Length 13.6 to 14.5 mm (n=2). Body elongate, parallel-sided, subcylindrical to slightly flattened. Dorsal surfaces orange to reddishbrown, covered with darkly pigmented tergal plates and branched spines. Head hypognathous, slightly flattened; antennae short, 3-segmented. Thoracic and abdominal terga with several pairs of branched spines; tergum A9 with a pair of long and narrow fixed urogomphi ( Fig. 7 ). Pupae. With the general appearance of other Erotylini (see Costa et al. 1988). Total length 12.5 mm; width 6.7 mm (n=2). With several spines or styli (sometimes branched) bearing a small apical seta ( Fig. 8 ). Color white to yellowish-brown, with dark brown styli, in recently pupated specimens and yellowish to reddish-brown in older pupae. A distinct white line from clypeus onto mesonotum is present. Adults. Tenerals (~ 11.5 mm long; n=5) with opaque coloration. Head with black medial spot. Pronotum yellowish-brown with black sparse color marks. Elytral with whitish elytral spots ( Fig. 10 ). Fully pigmented adults bright colored. Head and prothorax fully black. Elytra with spots conspicuously red ( Figs. 1 , 11 , 12 ). Males bearing a patch of setae at the center of abdominal ventrite I.

Biology and behavior. Most of the basidiomes of Lentinus substrictus (= Polyporus ciliatus ) was consumed by the female E. jaspidea during the four days following its capture ( Fig. 1 ). On the morning of June 14, 2016, the female oviposited 23 yellowish cylindrical eggs in the fungal hymenium ( Fig. 2 ). On June 17 to 18, eggs hatched and the first instar larvae readily fed on the fragment of L. substrictus ( Fig. 3 ). Gregariousness was observed ( Fig. 5 ) and the larval behavior was marked by a period of constant feeding followed by inaction. Neither negative nor positive phototaxis was observed. The ecdysis occurred only at night: larvae hang from the fungal host by an attachment at the abdominal apex and the subsequent instar emerged from the exuviae ( Fig. 4 ). Four different instars were recognized. An interesting behavior was observed when the larvae were manipulated: when their dorsum was touched with a tweeze, they promptly turned up their abdomen and attacked the tweeze with their urogomphi, resembling a scorpion arching its opisthosoma (Supplementary video at https://doi.org/10.5281/zenodo.7020682). It is plausible that such “scorpion-like behavior” may be a defensive strategy (see Discussion). The pupae remained attached to their own last larval exuviae and were suspended freely from the basidiome surface ( Figs. 8–9 ). The pupae had somewhat a persistent foul smell, probably caused by glandular secretion. Soon after their emergence, teneral adults remained apparently inactive for a few days ( Fig. 10 ). At the end of the cuticular pigmentation process, the fully pigmented adults began to feed on basidiomes of Favolus tenuiculus offered to them, especially those well moistened, avoiding the dry ones. Once basidiomes of F. tenuiculus have been completely consumed, they were replaced by the resupinate fungi. In field observations they were also found feeding on resupinate fungi ( Fig. 12 ). The adults of E. jaspidea consumed the basidiomes of both fungi. Despite their well-developed metathoracic wings, none of the adults tried to fly. One adult showed what seemed to be a precopulatory behavior, with the elytra left opened for some time before copula.

Rate of survival and additional notes. The oviposition has not been observed. The eggs were aggregated on the fungus hymenium ( Fig. 2 ), uncovered, and hatched on June 17th, after four days following oviposition ( Table 1 ). From the 23 eggs, five did not hatch. It was possible to observe the first sclerotized larval parts (tarsi and mandibles) within the eggs, probably used to rupture the chorion ( Fig. 3 ). The highest mortality (seven larvae) was observed in the first larval instar, which lasted seven days ( Table 1 ). The second larval instar (five days) had only one death and the third instar (nine days) had two deaths. The fourth larval instar was the longest (13 days) and the pupal stage lasted 14 days ( Table 1 ). The life span of the adults ranged from 32 to 56 days under laboratory conditions.

Figures

FIGURE 7. Third instar larvae of Erotylina jaspidea (Erichson, 1847). Scale bar = 2 mm.

FIGURE 12. Erotylina jaspidea (Erichson, 1847) feeding on resupinate fungi in Parque Estadual Dunas do Natal, Rio Grande do Norte, Northeast Brazil (June 2018).

FIGURES 1–2. Erotylina jaspidea (Erichson, 1847). 1. Adult female, mother of the studied immatures, scale bar = 2 mm. 2. Eggs right after oviposition, scale bar = 1 mm.

FIGURES 3–6. Erotylina jaspidea (Erichson, 1847). 3. Two eggs and the first hatched larva, scale bar = 1 mm. 4. Larvae at the end of the first instar, scale bar = 1 mm. 5. Gregarious feeding behavior of second instar larvae, scale bar = 2 mm. 6. Second instar larva in the center, among third instar larvae after ecdysis, scale bar = 1 mm.

FIGURES 8–9. Erotylina jaspidea (Erichson, 1847). 8. Pupae on the surface of Favolus tenuiculus P. Beauv., scale bar = 2 mm. 9. Pupae attached to exuviae, scale bar = 2 mm.

FIGURES 10–11. Erotylina jaspidea (Erichson, 1847). 10. Newly emerged adult (teneral), similar to the original description of Erotylina intermedia (Crotch, 1876) (see Discussion), scale bar = 2 mm. 11. Copulatory behavior (September 19, 2016), scale bar = 2 mm.