Differences in genitalia structure and function between subfamilies of longhorn beetles (Coleoptera: Cerambycidae)

Abstract

Beetle genitalia are usually described only for taxonomic purposes without considering the possible function of structures. Exceptions are sporadic detailed studies on single species. We studied genital structures in the subfamilies of Cerambycidae and outlined assumptions on the function of these structures and the implications for the phylogeny of the Cerambycidae. We found that male genitalia in particular are taxon-specific on a higher taxonomic level; e.g., the parameres are widely variable in Cerambycinae, while in most Lamiinae species they appear relatively uniform and differ from those of the Cerambycinae. Internal sac structures are very different among the various subfamilies. Small backwards-pointing spines are the most common armature of the internal sac. The female genitalia are less variable, although ovipositor morphology may differ among subfamilies. In most species, the connection between the mates during copulation is achieved by the long internal sac and the ovipositor only, whereas the median lobe and parameres are in contact with the female abdomen only at the beginning of copulation. Cerambycinae and Lepturinae have a basal swelling of the endophallus to prevent it from sliding back into the male abdomen during copulation. The long internal sac functions in connecting the mates and guaranteeing the sperm transfer.

Genital feelers: the putative role of parameres and aedeagal sensilla in Coleoptera Phytophaga (Insecta)

“…The same may apply also to Cleistolophus sp. and other weevils, as it was shown to be the case in most longhorn beetles (Cerambycidae, Hubweber and Schmitt 2009). …”

Bizarre mating in the entimine weevilPolydrusus picus

“…The orientation of projections toward the pedon results in minimal friction when the males insert the intromittent organ into the vagina, whereas strong friction is involved when the males pull back the endophallus inflated within the ovipositor. Similarly arranged projections on the endophallus were also observed in Cerambycidae and Chrysomelidae (Düngelhoef & Schmitt, ; Hubweber & Schmitt, ), but different types of the projections of the dorsal and ventral sides of the endophallus were not reported as shown in P. picus . The different projections perhaps have the additional function to stimulate the females, especially to induce them to release their ovipositor and possibly to support the extrusion process.…”

“…Inflation methods of the endophallus established by Hünefeld, Brehm, and Pohl () and van Dam () would likely yield more precise data. In addition, as Hubweber and Schmitt () pointed out, information on sensilla in the female vagina is scarce in general. To test possible functions of the projections, that is, stimulating females, female genital sensilla should be examined in detail in future investigations.…”

“…Unusual mating with the female ovipositor almost completely pulled out of the body is also known in many species of longhorn beetles (Hubweber & Schmitt, ) and must have evolved independently within Cerambycidae and Curculionidae. Further studies to understand their function and evolutionary background are necessary.…”

Revision of the European species of Omphale Haliday (Hymenoptera, Chalcidoidea, Eulophidae)

“…Examples of this are commonly found in e.g. Diptera (Grimaldi and Nguyen 1999), Coleoptera (Hubweber and Schmitt 2009), and Lepidoptera (Sohn and Nishida 2011). However, in the Hymenoptera, male genitalia usually show little variation at both the species and genus level (Michener 1956).…”