Luperini Gistel, 1848

Subtribe Luperini Gistel, 1848 View in CoL

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 View FIG ) 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 View FIG ). 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 View FIG ). Aulacophora cornuta Baly, 1879 ( Fig. 6E View FIG ), an unidentified New Guinea species ( Fig. 6D View FIG ), and A. luteicornis (Fabricius, 1801) ( Fig. 6G View FIG ) all had apical sclerites in the form of elongate tubes. A female of A. cornuta ( Fig. 6F View FIG ) 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 View FIG ). 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 View FIG ). 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 View FIG ). The male endophallus had robust spines ( Fig. 8A, B View FIG ), and the female vagina bore scars a short distance away from the male organ (arrows in Fig. 8A View FIG ). 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 View FIG ) showed some puncture wounds in the vagina, and the male endophallus ( Fig. 8E View FIG ) 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 View FIG ). The female ( Fig. 8D View FIG ) 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 View FIG ). 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 View FIG ).

A pair of Amphelasma decoratum (Jacoby, 1887) were found dried and in copula. When dissected ( Fig. 9A, B View FIG ), 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 View FIG ), and with a long tubular apical sclerite flanked by a pair of plates terminating in long spines ( Fig. 9C View FIG , inset). A female showed a single possible scar near the entrance of the vagina ( Fig. 9D View FIG ).

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 View FIG ). Two females were dissected; one had bursal scars ( Fig. 9F View FIG ), 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 View FIG ). 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 View FIG ); 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 View FIG ) and Schematiza ( Fig. 2C View FIG ). 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 View FIG ) 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 View FIG ), 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 View FIG ). In the dissected female, there was a line of scars in the vagina ( Fig. 10D View FIG ) 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 View FIG , inset); the female examined had markings in the vagina that could be abrasion damage ( Fig. 10F View FIG ). Pteleon brevicornis (Jacoby, 1887) had an endophallus covered with long cornuti ( Fig. 10G View FIG ), while the female ( Fig. 10H View FIG ) 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 View FIG ). 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 View FIG ). The female ( Fig. 11C View FIG ) 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 found in the genus Coeligetes Jacoby, 1884 , and apparently occurs in several allied genera. The endophallus in Coeligetes borneensis Mohamedsaid, 1994 was heavily sclerotized and lies along a depression in the dorsal side of the median lobe. The apex of the endophallus was curved up into a head-like structure capped with a dense brush of hair-like setae and bearing a pair of down-curved horns on the leading edge ( Fig. 11D, E View FIG ). The endophallus is capable of extending a short distance, as shown in Figure 11E View FIG , whereas in the drawings in Mohamedsaid (1994) and Bezdĕk (2016) it is shown in the retracted position. The female vaginal structure of C. borneensis is also unusual in that it is clearly broader than long (in all other species examined in this study the female internal structure was longer than broad, even if the bursa was distended by a spermatophore). In C. borneensis the bursa bears a pair of short spines just behind the lobe-like vaginal palpi, and a pair of probable scars on the rear wall of the bursa ( Fig. 11F View FIG ). Besides Coeligetes , four other East Asian genera show a similar development of the endophallus as a long sclerotized tube: Coeligetoides Bezdĕk, 2016 ( Bezdĕk 2016), Liroetis Weise, 1889 ( Bezdĕk 2021), Luperogala Medvedev & Samoderzhenkov, 1989 ( Bezdĕk 2017), and Siemssenius Weise, 1922 ( Lee 2016).

Section Monoleptites Chapuis, 1875

Representatives of this group of principally Old World genera have some of the most complex and potentially damaging endophalli yet found in Coleoptera . One North American Monoleptites in this study is currently listed under Metrioidea Fairmaire, 1881 , i.e., M. blakeae ( Wilcox, 1965) , but Beenen (2008, 2013) has determined that the genus Metrioidea should be limited to a small group of species from Fiji and New Caledonia. Metrioidea blakeae is consequently transferred here to the genus Monolepta , with the new combination Monolepta blakeae (Wilkox, 1965) n. comb.

The case of Monolepta elongata ( Fig. 1 View FIG A-D), introduced above, represents a confirmed case of female damage during copulation. Everted male endophalli from three species of Costa Rican Monolepta were figured in Flowers & Eberhard (2006: figs 22, 23, 25). A female Monoleptites (without an associated male) from Costa Rica showed scar points on the bursa ( Flowers & Eberhard 2006: fig. 24). In this study, similar structures and presumed damages for both sexes were found in other species: Monolepta blakeae n. comb. (male, Fig. 12A View FIG ; female, Fig. 12B, C View FIG ), Monolepta irazuensis ( Jacoby, 1888) (male, Fig. 12D View FIG ; female, Fig. 12E View FIG ); unidentified Monolepta from Ecuador ( Fig. 12F View FIG ) and Honduras (male, Fig. 13A View FIG ; female, Fig. 13B View FIG ).

Endophallic spiculae ( Wagner 2007) appeared to be differentiated into larger basal spines or hooks, and a more apical area of cornuti (very fine needles) and ranks of short, curved spiculae. The apical sclerite area (where fully everted) consisted of a thin curved tube flanked by a pair of leaf-like sclerites (as in Fig. 12A, D View FIG ). The unidentified Monolepta from Ecuador ( Fig. 12F View FIG ) differed from other New World species in the structure of its median lobe. Characteristic scar points were present in females ( Fig. 12B, C, E View FIG ), but in Monolepta blakeae n. comb., for which a series of females was available, only one ( Fig. 12B View FIG ) of six specimens presented scar points.

In three examined species of Old World Monolepta , the various spiculae on the endophalli were more morphologically subdivided than was the case in the New World species. A Monolepta sp. from Nigeria ( Fig. 13C View FIG ) had basal spines as long and almost as slender as the apical spiculae; the female ( Fig. 13D View FIG ) had characteristic puncture scars. In a Sumatran species the endophallus had a whorl of needle-like spiculae and several paddle-shaped apical sclerites ( Fig. 13E View FIG ). Large Monolepta laosensis Kimoto, 1989 (male, Fig. 13F View FIG ; female, Fig. 13G View FIG ) and an unidentified species from Vietnam (male, Fig. 13I View FIG ; female, Fig. 13J View FIG ) show the organization of the different spicula types in discrete endophallic regions. Scarring was evident in females of both these species.

A single male of the monoleptine Palaeosepharia truncata Laboissière, 1936 ( Fig. 13H View FIG ) showed a similar diversity and arrangement of spiculae to Monolepta (no female was available). Lee (2018) in a revision of Paleosepharia Laboissière, 1936 of Taiwan illustrates retracted spines of five species, all showing at least the potential of penetrating the female bursa. Rizki et al. (2016) redescribed and illustrated the type specimen of P. truncata , including a drawing of the median lobe with the endophallus within. Their description of the appearance of spiculae seen within the median lobe missed several features that are evident in the everted preparation (a third pair of strong basal spiculae and strong ventral comb-like spiculae). Also, their assessment that Paleosepharia endophalli are “simpler” than other in genera was not borne out by this study.

Specimens of the New World monoleptine Eusattodera Schaeffer, 1906 species were examined. The male endophallus ( Fig. 13K View FIG ) differed from other monoleptines in this study by having a pair of sclerotized basal plates in addition to spiculae and cornuti. Two females ( Fig. 13L View FIG ) had evidence of mating (spermatophore material in the bursae), but no scars were found on bursal or vaginal membranes.

A male and a female of Candezea semiviolacea (Fauvel, 1862) from New Caledonia were examined. The endophallus could not be everted intact from the very narrow and elongate median lobes, but it bore leaf-like apical sclerites and longitudinal lines of medium-length spiculae. The female, however, showed no bursal scars, although there was a spermatophore within.

SURVEY OF FEMALE STRUCTURES

Development of sclerotized structures in the female bursae were also found to be widely distributed in the galerucine genera in this survey, and appeared to be at least somewhat correlated with modifications of the male endophalli. The majority of taxa studied had no modifications in the either the bursa or the vagina; see the female of Amphelasma decoratum ( Fig. 9B View FIG ). Most of the Galerucini genera studied had unsclerotized bursae, although in Monoxia angularis , the female vagina had longitudinal fields of spinelets ( Fig. 2B View FIG ).

In the Metacyclini , several types of modified bursal membranes were found. The Hecataeus female had two lateral areas covered with short denticles ( Fig. 4E View FIG ), whereas in species of Malacorhinus ( Fig. 4G View FIG ) and Exora the lateral areas had a series of sclerotized bars covered with small bumps. A different arrangement was found in the female of Masurius sp. , in which the vagina had several large plate-like sclerites ( Fig. 4B View FIG ). Byblitea jansoni appeared to have a weakly sclerotized central area of the bursa, which appeared to contain abrasions ( Fig. 3F View FIG ).

In the Luperini examined, the female genital armature ranged from nonexistent (e.g. in the copulating pair of Amphelasma , Fig. 9A, B View FIG ) to heavily sclerotized sets of jaw-like structures (e.g. in Monoleptites).

In the Scelidites, the female of Synetocephalus bivittatus had a dense field of denticles on its inside surface ( Fig. 10F View FIG ), whereas females of other genera studied had no modifications. In Exosomites, the female of Cneorane femoralis had entire posterior part of the bursa lined with shard-like sclerites ( Fig. 11C View FIG ).

Galerucines belonging to the section Monoleptites have males with the most elaborate (and dangerous-looking) endophallic modifications ( Figs 12A, D, F View FIG ; 13A, C, E, F, H, I, K View FIG ), matched by females with the most heavily sclerotized bursal teeth and plates ( Figs 12B, C, E View FIG ; 13B, D, G, J, L View FIG ). In addition to the studied taxa, females in many other species and genera of Monoleptites described from Africa and Southeast Asia also have either one or two pairs of toothed, sclerotized processes within the bursa (e.g. Wagner & Scherz 2002; Wagner 2007, 2020).