Acalymma;Amphelasma;Androlyperus;Cerotoma;Cyclotrypema;Diabrotica;Eusattodera;Keitheatus;Luperosoma;Lygistus;Metrioidea;Neobrotica;Paranapiacaba;Paratriarius;Phyllecthris;Phyllobrotica;Pseudoluperus;Pteleon;Scelida;Scelolyperus;Synetocephalus;Trachys

Subtribe Luperini Gistel, 1848 Section Aulacophorites Chapuis, 1875 Five species of the large Asian genus Aulacophora Chevrolat, 1836 were examined. Aulacophora antennata Baly, 1886 had a short, robust, lightly sclerotized endophallus with a pair of curved sclerotized horns on the dorsal side at the base, and a large, heavily sclerotized apical sclerite (Fig. 6A) and a complex apical structure with brushes of fine setae. A female had a vagina with a relatively thick membrane with a pair of small spurs in the vagina and two small abraded areas at the rear wall of the bursa (Fig. 6B). This suggests male stimulation rather than traumatic penetration during mating. Four other species of Aulacophora all had a different basic pattern in the male aedeagus: relatively short membranous endophalli with patches of small spines or denticles, ending in relatively long, heavily sclerotized apical sclerites. In A. bicolor (Weber, 1801) the endophallus had only very small patches of denticles along with a strong hook-shaped apical sclerite (Fig. 6C). Aulacophora cornuta Baly, 1879 (Fig. 6E), an unidentified New Guinea species (Fig. 6D), and A. luteicornis (Fabricius, 1801) (Fig. 6G) all had apical sclerites in the form of elongate tubes. A female of A. cornuta (Fig. 6F) had numerous apparent scars or abrasions on the bursa; the sizes and numbers did not correspond in any obvious way with the male tube or hook; however, females of A. luteicornis showed no signs of bursal damage. In Agetocera similis Chen, 1997 the male has a membranous, branched endophallus with each branch terminating in a sharp spike (Fig. 7A). Despite the impressive armature of the male, the female available for study showed no signs of damage, and she had a large sclerotized structure in the bursa (Fig. 7B). Lee et al. (2010), in their revision of the Agetocera Hope, 1831 of Taiwan, give line drawings of male median lobes with tracings of internal sclerites. It appears that their species also have “three-spike” endophalli similar to those of A. similis. Section Diabroticites Chapuis, 1875 A pair of Diabrotica undecimpunctata howardi Barber, 1947, mounted in copula, was dissected with the male and female genitalia in position (Fig. 8A). The male endophallus had robust spines (Fig. 8A, B), and the female vagina bore scars a short distance away from the male organ (arrows in Fig. 8A). Although not obvious in the photo due to KOH clearing, the bursa also contained a large spermatophore. Derunkov et al. (2013) have published an electronic identification tool, which includes photos of everted endophalli for most of the species of Diabrotica Chevrolat, 1836 of North and Central America. These endophalli show a similar pattern of a relatively short membranous tube with from three to five robust sclerites variously developed as spikes, hooks, or serrated pads in different combinations. Copulation in D. undecimpunctata was also studied in flash-frozen beetle pairs by Tallamy et al. (2002). They found that the female has a fold in the vagina that she can use to exclude the entrance of the male median lobe. Male courtship activities can induce the female to relax the fold and permit entrance. However, the authors did not mention either the endophallus or the endophallic spines in their study. A pair of Acalymma Barber, 1947 specimens from Dominica, preserved in copula was dissected, although the pair separated during this process. The female (Fig. 8F) showed some puncture wounds in the vagina, and the male endophallus (Fig. 8E) was a small, membranous lobe with a small curved spine and a very small knob at the apical end. Acalymma subaeneum Jacoby, 1887 (not shown) had two small sclerites in the endophallus, similar to the Dominica male; in the female, the vagina had no evidence of scarring. The male Isotes rubripennis (Erichson, 1847) had a pair of backward-facing hooks at the base of the endophallus, reminiscent of similar structures found in the Metacyclini, and a spike-like apical sclerite (Fig. 8C). The female (Fig. 8D) had a few scar-like dots at the entrance of the bursa. Behind these, there was a transverse band of small black sclerites, arranged in a scale pattern. These are presumably structures related to processing the spermatophore. The vagina of Isotes dilatata (Jacoby, 1887) (not shown) had several apparent scars but lacked the sclerotized band of I. rubripennis. No males of this species were available. In a Paranapiacaba Bechynĕ, 1958 species from Argentina, the male had a pair of sharp spines at the base of the endophallus and a long spiraling sclerite bearing a line of small bumps (Fig. 8G, H). A dissected female had an unequal pair of small plate-shaped bursal sclerites, and some very small possible scars near the opening of the bursa (Fig. 8I). A pair of Amphelasma decoratum (Jacoby, 1887) were found dried and in copula. When dissected (Fig. 9A, B), the male had the endophallus covered with fine denticles, similar to that described for the bruchid genus Acanthoscelides Schilsky, 1905 (Schmitt et al. 2023) and the Eumolpinae tribes Bromiini Baly, 1865 and Typophorini Baly, 1865 (Flowers 1999). The female Amphelasma had no sclerotized modifications on the bursa. A species of Zischkaita Bechynĕ, 1956 (not illustrated) also had a completely membranous male endophallus; a female was not dissected for this genus. In Gynandrobrotica ventricosa (Jacoby, 1878), the endophallus was mostly membranous with a dorsal crest that has a sclerotized crenulate ridge along its length (Fig. 9C), and with a long tubular apical sclerite flanked by a pair of plates terminating in long spines (Fig. 9C, inset). A female showed a single possible scar near the entrance of the vagina (Fig. 9D). Section Phyllecthrites Horn, 1892 Several Luperosoma subsulcata (Horn, 1893) were examined. Males had flat arrowhead-shaped plates at the tip of the endophallus; these plates had trailing, curved, spine-like projections (Fig. 9E). Two females were dissected; one had bursal scars (Fig. 9F), whereas the other had no damage. Two copulating pairs of Phyllecthris dorsalis (Olivier, 1808) were studied. Both were dry mounted on points, and both broke apart during specimen preparation. Rupture was at the point where the tip of the male median lobe entered the female, leaving the entire endophallus intact inside the bursa. The endophallus was membranous, tipped with a thin chevron-shaped sclerite with a moveable pointed spike (Fig. 9G, J). During copulation, the spike is deployed at an angle to the main axis of the median lobe. In one of the pairs dissected, the spike penetrated the bursa (Fig. 9I); however, in the other pair the spike remained inside the bursa, which was uninjured. In both dissected pairs there was evidence of spermatophore material in the bursae. Section Scelidites Chapuis, 1875 Most genera in this group are found in Africa, Madagascar, and western North America (Seeno & Wilcox 1982). Six genera from the southwestern United States were examined in this study. Triarius trivittatus Horn, 1893 (not shown) had a long membranous endophallus with a thin flexible sclerite running along its length similar to the male Monoxia (Fig. 2A) and Schematiza (Fig. 2C). Amplioluperus Viswajyothi & Clark, 2022, Scelida Chapuis, 1875, and Scelolyperus Crotch, 1874 all had a similar form of an endophallus that consisted of a thin membranous sac bearing rows or fields of small sharp spines or hooks. Amplioluperus cyanella (Horn, 1895) (not shown) and Scelida nigricornis (Jacoby, 1888) (Fig. 10A) both had simple tubular median lobes with endophalli densely covered with short, sharp spines; the females of these species showed no signs of scarring. Scelida flaviceps (Horn, 1893) (Fig. 10B), however, had a very different form of the median lobe from S. nigricornis, but a similar endophallus with a membranous tube bearing a field of spines. The female of this species also had no evidence of puncture scarring in the vagina. In Scelolyperus lecontii (Crotch, 1873) the male has a pair of large blade-like sclerites at the tip of the median lobe, and the endophallus is almost entirely membranous with two lines of small, hooked sclerites (Fig. 10C). In the dissected female, there was a line of scars in the vagina (Fig. 10D) corresponding in size to the line of hooks found in the male. In Synetocephalus bivittatus (LeConte, 1859), the male had a very large and complicated apical sclerite, as well as basal spines (Fig. 10E, inset); the female examined had markings in the vagina that could be abrasion damage (Fig. 10F). Pteleon brevicornis (Jacoby, 1887) had an endophallus covered with long cornuti (Fig. 10G), while the female (Fig. 10H) showed clear evidence of bursal tissue scar damage. In a revision of Charaea Baly, 1878 from Taiwan, Bezdĕk & Lee (2014) illustrate several everted endophalli that show strikingly similar patterns of cornuti to Pteleon, although Charaea is currently placed in a different section of the Luperina, the Eumelepities Wilcox, 1973 (Seeno & Wilcox 1982). Section Phyllobroticites Chapuis, 1875 In Phyllobrotica costipennis Horn, 1893 the male had a simple membranous endophallus without any trace of sclerotized structures (Fig. 11A). The female (not shown) had no scars or sclerotized structures in the vagina or bursa. Section Exosomites Wilcox, 1973 This is a diverse African and Southeast Asian group with varied examples of endophallic sclerites found in the few genera so far investigated. In Cneorane femoralis Jacoby, 1888 the endophallus was elongate and bore a dense field of long, sharp cornuti on the apical third, as well as a blade-like apical sclerite at the tip (Fig. 11B). The female (Fig. 11C) had a field of sharp, black sclerites on the inside of the vagina adjacent to the bursa, presumably involved with processing the spermatophore. Behind this were small scarred areas, possibly due to contact with the male cornuti. One of the stranger modifications of the male endophallus was