Angela Roggero

Rapid shape divergences between natural and introduced populations of a horned beetle partly mirror divergences between species

SUMMARY Onthophagus taurus is a polyphenic beetle in which males express alternative major (horned) and minor (hornless) morphologies largely dependent on larval nutrition. O. taurus was originally limited to a Turanic–European–Mediterranean distribution, but became introduced to several exotic regions in the late 1960s. Using geometric morphometrics, we investigate the present‐day morphological shape differentiation patterns among native (Italian) and introduced (Western Australian and Eastern US) populations. We then contrast these divergences to those observed between native O. taurus and its sympatric sister species O. illyricus. Our analysis failed to find significant divergences between O. taurus populations in external morphological traits (head, pronotum) when analyses were conducted separately for each sex. However, when sexes and male morphs were analyzed together, three important differences among populations emerged. First, relative warp analyses showed that native and introduced populations diverged in certain shape components that normally distinguish major and minor male morphs. Second, comparison of covariation of body regions (head vs. pronotum) in the three populations showed that populations diverged in the nature of this covariation, suggesting that different body regions are not totally constrained to evolve in concert. Lastly, and most importantly, the analysis of genitalic shape revealed little to no divergence of female genitalia, but unexpected substantial differentiation of male genitalia among the three O. taurus populations. This suggests that genitalic shape divergence can occur extremely rapidly even in the absence of sympatry and possible reinforcement, and that the genitalia of males and females may diverge independent of one another, at least during the early stage of interpopulational divergence. Interpopulation divergences in O. taurus mirrored aspects of interspecific divergences between O. taurus and O. illyricus in some cases but not others.

Systematics and phylogeny of Eodrepanus, a new Drepanocerine genus, with comments on biogeographical data (Coleoptera: Scarabaeidae: Oniticellini)

We describe here Eodrepanus gen. nov., currently comprising nine species, six previously assigned to the genus Drepanocerus and three described as new (namely, E. morgani sp. nov., E. paolae sp. nov. and E. coopei sp. nov.). Two of the new species have an Afrotropical distribution, while the last is an Eemian fossil species from England. Maximum parsimony was used to analyse reciprocal relationships among the species of Eodrepanus gen. nov., and four of the 24 species remaining in Drepanocerus. Support for these phylogenies was evaluated using the Bootstrap method and Bayesian inference as implemented in MrBayes. The biogeography of Eodrepanus gen. nov. was analysed using several different methods, namely, analysis of similarity (Ochiai Index), dispersal–vicariance analysis and parsimony analysis of endemicity.

On the evolution of shape and size divergence in Nebria (Nebriola) ground beetles (Coleoptera, Carabidae)

Ground beetles include many species of rather recent evolutionary origin that are extremely similar in their external morphology. We used geometric morphometrics to quantify the relative degree of morphological divergence in three closely related polytypic alpine species of the genus Nebria, subgenus Nebriola (Nebria cordicollis, N. laticollis and N. fontinalis). To examine evolutionary patterns, we adopted a hierarchical design, using both shape and size to discriminate between species, subspecies within species, and populations within subspecies. A semilandmark-based approach was used to describe the pronotum, elytron and median lobe of the aedeagus. The three closely related species diverged significantly in shape and size. There were clear interspecific differences in the shape of external traits (elytron and pronotum) and of the median lobe of the aedeagus. Furthermore, species also diverged in body size, and in the relative size of traits (evaluated by computation of their static allometries). Shape differences among subspecies and populations were more limited. However, the three subspecies of N. cordicollis considered, N. c. cordicollis, N. c. kochi and N. c. winkleri, showed three distinct body sizes and differences in relative size of the elytron. A few size differences were also evident between distinct populations. These results seem to suggest that size may diverge more rapidly than shape in Nebriola ground beetles. Both at the species and subspecies level, body size order was not reflected in the relative size order, indicating that body size and relative size of traits do not necessarily evolve in concert.

Interspecific shape divergence in Aphodiini dung beetles: the case of Amidorus obscurus and A. immaturus (Coleoptera: Scarabaeoidea)

The dung beetles Amidorus obscurus and A. immaturus are nearly indistinguishable, being characterized by a marked constancy in external morphological traits and little sexual dimorphism in adults. We studied two syntopic populations from the Italian Alps by means of geometric morphometric analyses. To identify possible undetected shape differences between species, we focused on the head, pronotum and scutellum (three external traits) and the epipharynx. Results indicate that the external traits are rather similar in the two species, whereas the epipharynx is clearly different. Interspecific differences in the aedeagus were also taken into account; these are noteworthy because parameres of A. immaturus differ in shape and are at least three times longer than those of A. obscurus. If it is assumed that the diversification of the two species took place during the quaternary ice age, A. immaturus would have evolved these marked differences rather quickly, in keeping with the hypothesis of rapid genital evolution. In an ontogenetic trajectory framework, we also considered the morphology of larvae. Interspecific divergence in the shape of the epipharynx is already evident at the preimaginal stage, whereas that of the genital disc is not. Accordingly, we hypothesise that the feeding and reproductive traits of these two species diverged morphologically when they become functional. Finally, by considering recent advances in ecological and evolutionary knowledge of dung beetles, the pattern of relative constancy in external morphology exhibited by the tribe Aphodiini, and that of great morphological diversification displayed by Onthophagini, were compared, and hypotheses about the origins of these differences discussed.

Analysis of shape variation in Phalops Erichson genus (Coleoptera, Scarabaeoidea, Onthophagini)

Abstract In order to obtain data on interspecific variation among the species belonging to Phalops genus, shape variation in genitalia armures was investigated using geometric morphometric methods. For males, shape variation was analyzed using Generalized Procrustes Analysis (GPA), while in females shape variation of the sde‐rotized area of the vagina was examined using both GPA and elliptic Fourier analysis. For each sex, patterns of shape variation among species were examined using both relative warp analysis and cluster analysis, and concordance of male and female shape variation was assessed with both a Mantel test and two‐block partial least squares analysis. There was little correspondence between male and female genitalia shape. Finally, results from these analyses were compared to the phylogenetic relationships among the taxa.

Description of two new species of Apostibes Walsingham, 1907 with some synonymic and phylogenetic accounts of the genus (Lepidoptera, Scythridi- dae)

Abstract Two new species of Apostibes Walsingham are described: A. dhahrani n. sp. from Saudi Arabia and A. afgbana n. sp. from Afghanistan. Their genital features are illustrated. A new synonymy is proposed for Coleophorides bahrlutella Amsel, 1935 with A. griseolineata Walsingham, 1907. The lectotype of Scythris inota Meyrick is established and the taxon is transferred to the genus Apostibes. The Parsimony analysis was carried only on the five Palaearctic species of the genus.

New Scythrididae (Lepidoptera, Gelechioidea) from Middle and Far East

Abstract Four new scythridid species – Scythris acusella n. sp., Scythris ampullella n. sp., Scythris brummanae n. sp., and Scythris kolachii n. sp. – are described from the Eastern Palearctic region. We assigned S. brummanae to the S. aerariella species-group, according to its genital features. At present S. acusella, S. ampullella and S. kolachii could not be included in any known species group on the basis of the characters of genitalia.

Tibiodrepanus tagliaferrii - a new Afrotropical Drepanocerina species (Coleoptera: Scarabaeidae: Oniticellini), with notes on phylogeny and distribution of the genus

We examined the genera Tibiodrepanus Krikken, 2009 (four Oriental and one Palaearctic species) and Sulcodrepanus Krikken, 2009 (one Afrotropical species), using type specimens and non-type specimens, in order to assess the systematic consistency of the two taxa. Within this framework, we also considered the genera Afrodrepanus Krikken, 2009 (two species) and Drepanocerus Kirby, 1828 (two species) employing sets of traits from external morphology, the genitalia of both sexes and the epipharynx. The genus Cyptochirus Lesne, 1900 was chosen as an outgroup. A new species—Tibiodrepanus tagliaferrii sp. nov.—was described based on four females from Cameroon and Namibia. The phylogenetic analyses confirmed that the Tibiodrepanus and Sulcodrepanus species were closely related, yet it did not support the hypothesis of a generic or subgeneric separation of the two taxa. Hence, we establish Sulcodrepanus as a junior synonym of Tibiodrepanus, new synonymy. The genus Tibiodrepanus shows a disjunct Afrotropical-Oriental (common to many other Drepanocerina genera) and Southeastern Palaearctic (Hindu Kush, Afghanistan) distribution pattern.

Four new species of Scythrididae (Lepidoptera: Gelechioidea) from Irano–Turanian area, with notes on taxonomy and distribution

Four new scythridid species are described: Scythris kabulella sp. nov. and S. claudiae sp. nov. from Afghanistan, S. alborzensis sp. nov. from Iran and S. bifasciella sp. nov. from Iran and Turkey. Scythris kabulella is closely related to S. bagdadiella Amsel, 1949 and is assigned to the S. bagdadiella species group because of its genital features. Scythris claudiae is also assigned to Scythris pascuella species group due to its genital features. At present, S. alborzensis and S. bifasciella could not be assigned to any known species group.

Evidence for Male Horn Dimorphism and Related Pronotal Shape Variation in Copris lunaris (Linnaeus, 1758) (Coleoptera: Scarabaeidae, Coprini)

Male horn dimorphism is a rather common phenomenon in dung beetles, where some adult individuals have well-developed head horns (i.e., major males), while others exhibit diminished horn length (i.e., minor males). We focused on horn dimorphism and associated head and pronotum shape variations in Copris lunaris. We examined the allometric relationship between horn length (i.e., cephalic and pronotal horns) and maximum pronotum width (as index of body size) by fitting linear and sigmoidal models for both sexes. We then asked whether head and pronotum shape variations, quantified using the geometric morphometric approach, contributed to this allometric pattern. We found that female cephalic and pronotal horn growth showed a typical isometric scaling with body size. Horn length in males, however, exhibited sigmoidal allometry, where a certain threshold in body size separated males into two distinct morphs as majors and minors. Interestingly, we highlighted the same allometric patterns (i.e., isometric vs. sigmoidal models) by scaling horn lengths with pronotum shape, making evident that male horn dimorphism is not only a matter of body size. Furthermore, the analysis of shape showed that the three morphs had similar heads, but different pronota, major males showing a more expanded, rounded pronotum than minor males and females. These morphological differences in C. lunaris can ultimately have important functional consequences in the ecology of this species, which should be explored in future work.