Phylogeography and DNA-based species delimitation provide insight into the taxonomy of the polymorphic rose chafer Protaetia (Potosia) cuprea species complex (Coleoptera: Scarabaeidae: Cetoniinae) in the Western Palearctic

Metabolic cost of flight and aerobic efficiency in the rose chafer, Protaetia cuprea (Cetoniinae)

Rose chafer beetles (Protetia cuprea) are pollinators as well as agricultural pests, flying between flowers and trees while foraging for pollen and fruits. Calculating the energy they expend on flying during foraging activity faces the challenge of measuring the metabolic rate (MR) of free-flying insects in an open space. We overcame this challenge by using the bolus injection of ¹³ C Na-bicarbonate technique to measure their metabolic energy expenditure while flying in a large flight arena. Concurrently, we tracked the insects with high-speed cameras to extract their flight trajectory, from which we calculated the mechanical power invested in flying for each flight bout. We found that the chemical (metabolic) energy input converted to mechanical flight energy output at a mean efficiency of 10.4% ± 5.2%, with a trend of increased efficiency in larger conspecifics (efficiency scaled with body mass to the power of 1.4). The transition in the summer from a diet of pollen to that of fruits may affect the energy budget available for foraging. Starved P. cuprea, feeding on apples ad libitum, increased their body mass by an average of 6% in 2 h. According to our calculations, such a meal can power a 630-m flight (assuming a carbohydrate assimilation efficiency of 90%). Pollen, with a low water and carbohydrate content but rich in proteins and lipids, has a higher caloric content and should assimilate differently when converting food to flight fuel. The high cost of aerial locomotion is inherent to the foraging behavior of rose chafers, explaining their short flight bouts followed by prolonged feeding activity.

Variations in genetic structure and male genitalia suggest recent lineage diversification in the Neotropical dung beetle complex Canthon cyanellus (Scarabaeidae: Scarabaeinae)

We analysed the genetic divergence and morphology of the aedeagus (i.e. phallobase and parameres) in Canthon cyanellus at different geographical levels. The results from both approaches were compared with the current taxonomic assignment of the C. cyanellus complex, which includes three subspecies. We found a high variation in all the morphological characters of the aedeagus in the populations analysed; the morphometric variation was not geographically structured, either by population or by region. The genealogical analysis indicates a significant genetic structure that does not match either the morphological variation in the male genitalia or the previous subspecific taxonomic classification. Our results suggest that the morphological variation of the aedeagus is seemingly not an isolating reproductive barrier and that the intra- and interpopulation morphological variability of the aedeagus in the C. cyanellus complex does not permit the division into several species. We suggest that other evolutionary forces, such as genetic drift and sexual selection, have influenced the evolution of the male genitalia and the incipient differentiation of this species complex.

Hiding in plain sight: DNA barcoding suggests cryptic species in all ‘well-known’ Australian flower beetles (Scarabaeidae: Cetoniinae)

DNA barcode data is presented for Australian cetoniine flower beetles to aid with species discovery and guide revisionary taxonomy. Sequences of the COI gene’s DNA barcode region were acquired from 284 cetoniine specimens, covering 68 described species and 33 genera. This equates to 48% of the known species and 83% of the genera which occur in Australia. Results suggest up to 27 putative undescribed species in our sample, only 11 of which were suspected to be undescribed before this study, leaving 16 unexpected (“cryptic”) species. The Australian cetoniine fauna may hence be increased by up to 19%. An unanticipated result of the work is that each of the five most visible and commonly collected Australian cetoniine species, Eupoecila australasiae (Donovan, 1805), Neorrhina punctatum (Donovan, 1805), Glycyphana (Glycyphaniola) stolata (Fabricius, 1781), Chondropyga dorsalis (Donovan, 1805) and Bisallardiana gymnopleura (Fischer, 1823), have unexpectedly high diversity in DNA barcode sequences and were consequently split into multiple clusters, possibly indicating the presence of cryptic species.

New species of Xiphoscelis Burmeister, 1842 (Coleoptera, Scarabaeidae, Cetoniinae) from arid regions of South Africa and Namibia

Two new species of the southern African genus Xiphoscelis Burmeister, 1842 are recognised and described, X.braunsisp. nov. from the Eastern and Western Cape Karoo (South Africa) and X.namibicasp. nov. from the Huns Mountains of southern Namibia and adjacent ranges in South Africa. These were previously overlooked and grouped together with X.schuckardi Burmeister, 1842, but further material and more in-depth analyses have now revealed their clear separation on the basis of key diagnostic features, including clypeal structure, metatibial spur development and aedeagal shape. The densely and coarsely costate elytral structure and the black to brown colour of these species are symplesiomorphies shared with a number of the most primitive genera among the African Cetoniinae. However, these characters also reflect the convergent adaptation to hot and arid conditions they share with several other species occurring in this region. Phylogenetic relationships of the genus with other Cetoniinae are explored using the larval characters highlighted in the description of the 3^rd instar larva of X.braunsisp. nov. The extraordinary hypertrophy observed in the male metatibial spur of species in this genus, and particularly in X.schuckardi, appears to represent a defence mechanism against potential predators on the ground, apart from playing a role during mating.