Some flying beetles have peculiar functional properties of their elytra, if compared with the vast majority of beetles. A “typical” beetle covers its pterothorax and the abdomen from above with closed elytra and links closed elytra together along the sutural edges. In the open state during flight, the sutural edges diverge much more than by 90°. Several beetles of unrelated taxa spread wings through lateral incisions on the elytra and turn the elytron during opening about 10-12° (Cetoniini, Scarabaeus, Gymnopleurus) or elevate their elytra without partition (Sisyphus, Tragocerus). The number of campaniform sensilla in their elytral sensory field is diminished in comparison with beetles of closely related taxa lacking that incision. Elytra are very short in rove beetles and in long-horn beetles Necydalini. The abundance of sensilla in brachyelytrous long-horn beetles Necydalini does not decrease in comparison with macroelytrous Cerambycinae. The strong reduction of the sensory field was found in brachyelytrous Staphylinidae. Lastly, there are beetles lacking the linkage of the elytra down the sutural edge (stenoelytry). Effects of stenoelytry were also not uniform: Oedemera and flying Meloidae have the normal amount of sensilla with respect to their body size, whereas the sensory field in the stenoelytrous Eulosia bombyliformis is 5-6 times less than in chafers of the same size but with normally linking broad elytra.
Recent adaptive radiations provide striking examples of convergence [1-4], but the predictability of evolution over much deeper timescales is controversial, with a scarcity of ancient clades exhibiting repetitive patterns of phenotypic evolution [5, 6]. Army ants are ecologically dominant arthropod predators of the world’s tropics, with large nomadic colonies housing diverse communities of socially parasitic myrmecophiles . Remarkable among these are many species of rove beetle (Staphylinidae) that exhibit ant-mimicking “myrmecoid” body forms and are behaviorally accepted into their aggressive hosts' societies: emigrating with colonies and inhabiting temporary nest bivouacs, grooming and feeding with workers, but also consuming the brood [8-11]. Here, we demonstrate that myrmecoid rove beetles are strongly polyphyletic, with this adaptive morphological and behavioral syndrome having evolved at least 12 times during the evolution of a single staphylinid subfamily, Aleocharinae. Each independent myrmecoid clade is restricted to one zoogeographic region and highly host specific on a single army ant genus. Dating estimates reveal that myrmecoid clades are separated by substantial phylogenetic distances-as much as 105 million years. All such groups arose in parallel during the Cenozoic, when army ants diversified into modern genera  and rose to ecological dominance [13, 14]. This work uncovers a rare example of an ancient system of complex morphological and behavioral convergence, with replicate beetle lineages following a predictable phenotypic trajectory during their parasitic adaptation to host colonies.
- Proceedings of the National Academy of Sciences of the United States of America
- Published almost 6 years ago
Foldable wings of insects are the ultimate deployable structures and have attracted the interest of aerospace engineering scientists as well as entomologists. Rove beetles are known to fold their wings in the most sophisticated ways that have right-left asymmetric patterns. However, the specific folding process and the reason for this asymmetry remain unclear. This study reveals how these asymmetric patterns emerge as a result of the folding process of rove beetles. A high-speed camera was used to reveal the details of the wing-folding movement. The results show that these characteristic asymmetrical patterns emerge as a result of simultaneous folding of overlapped wings. The revealed folding mechanisms can achieve not only highly compact wing storage but also immediate deployment. In addition, the right and left crease patterns are interchangeable, and thus each wing internalizes two crease patterns and can be folded in two different ways. This two-way folding gives freedom of choice for the folding direction to a rove beetle. The use of asymmetric patterns and the capability of two-way folding are unique features not found in artificial structures. These features have great potential to extend the design possibilities for all deployable structures, from space structures to articles of daily use.
Myrmecophiles-species that depend on ant societies-include some of the most morphologically and behaviorally specialized animals known . Remarkable adaptive characters enable these creatures to bypass fortress-like security, integrate into colony life, and exploit abundant resources and protection inside ant nests [2, 3]. Such innovations must result from intimate coevolution with hosts, but a scarcity of definitive fossil myrmecophiles obscures when and how this lifestyle arose. Here, we report the earliest known morphologically specialized and apparently obligate myrmecophile, in Early Eocene (∼52 million years old) Cambay amber from India. Protoclaviger trichodens gen. et sp. nov. is a stem-group member of Clavigeritae, a speciose supertribe of pselaphine rove beetles (Coleoptera: Staphylinidae) heavily modified for myrmecophily via reduced mouthparts for trophallaxis with worker ants, brush-like trichomes that exude appeasement compounds, and fusions of many body and antennal segments [4, 5]. Protoclaviger captures a transitional stage in the evolutionary development of this novel body plan, most evident in its still-distinct abdominal tergites. The Cambay paleobiota marks one of the first occurrences in the fossil record of a significant presence of modern ants . Protoclaviger reveals that sophisticated social parasites were nest intruders throughout, and probably before, the ascent of ants to ecological dominance, with ancient groups such as Clavigeritae primed to radiate as their hosts became increasingly ubiquitous.
Dead ant walking: a myrmecophilous beetle predator uses parasitoid host location cues to selectively prey on parasitized ants
- Proceedings. Biological sciences / The Royal Society
- Published about 4 years ago
Myrmecophiles (i.e. organisms that associate with ants) use a variety of ecological niches and employ different strategies to survive encounters with ants. Because ants are typically excellent defenders, myrmecophiles may choose moments of weakness to take advantage of their ant associates. This hypothesis was studied in the rove beetle, Myrmedonota xipe, which associates with Azteca sericeasur ants in the presence of parasitoid flies. A combination of laboratory and field experiments show that M. xipe beetles selectively locate and prey upon parasitized ants. These parasitized ants are less aggressive towards beetles than healthy ants, allowing beetles to eat the parasitized ants alive without interruption. Moreover, behavioural assays and chemical analysis reveal that M. xipe are attracted to the ant’s alarm pheromone, the same secretion used by the phorid fly parasitoids in host location. This strategy allows beetles access to an abundant but otherwise inaccessible resource, as A. sericeasur ants are typically highly aggressive. These results are the first, to our knowledge, to demonstrate a predator sharing cues with a parasitoid to gain access to an otherwise unavailable prey item. Furthermore, this work highlights the importance of studying ant-myrmecophile interactions beyond just their pairwise context.
In recent surveys carried out in Brazil, we detected two new species of Termitomorpha Wasmann, a genus of Termitogastrina (Aleocharinae, Corotocini). This genus is easily recognizable in the subtribe by the evenly convex and smooth pronotum. The new species are: Termitomorpha sinuosa Caron, Bortoluzzi Rosa sp. nov., and Termitomorpha alata Caron Bortoluzzi, sp. nov. Both species are here described and illustrated, including scanning electron photographs. Their host termites were identified as species of Nasutitermes. The key to species of Termitomorpha is updated based on recent literature.
Pselaphinae is a species-rich beetle subfamily found globally, with many exhibiting myrmecophily-a symbiotic association with ants. Pselaphine-ant associations vary from facultative to obligate, but direct behavioral observations still remain scarce. Pselaphines are speciose and ecologically abundant within tropical leaf litter invertebrate communities where ants dominate, implying a potentially important ecological role that may be affected by habitat disturbances that impact ants. In this study, we measured and analyzed putative functional traits of leaf litter pselaphines associated with myrmecophily through morphometric analysis. We calculated “myrmecophile functional diversity” of pselaphines at different sites and examined this measure’s relationship with ant abundance, in both old growth and logged rainforest sites in Sabah, Borneo. We show that myrmecophile functional diversity of pselaphine beetles increases as ant abundance increases. Old growth rainforest sites support a high abundance of ants, which is associated with a high abundance of probable myrmecophilous pselaphines. These results suggest a potential link between adult morphological characters and the functional role these beetles play in rainforest litter as ecological interaction partners with ants.
This study determined the direct, indirect, or both effects of pesticides on the rove beetle, Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae), and the insidious flower bug, Orius insidiosus (Say) (Hemiptera: Anthocoridae). The pesticides evaluated were Capsicum oleoresin extract, garlic oil, and soybean oil; cyantraniliprole; flupyradifurone; GS-omega/kappa-Hxtx-Hv1; Isaria fumosorosea; tolfenpyrad; pyrethrins; and spinosad. One experiment was conducted in a greenhouse with rove beetle adults exposed to growing medium applications of cyantraniliprole. The number of live and dead rove beetle adults was determined after 10 d. Four additional experiments were conducted under laboratory conditions. Rove beetle or insidious flower bug adults were individually placed into Petri dishes with filter paper treated with the pesticides. After 24, 48, 72, and 96 h, the number of live and dead adults of both natural enemies was recorded. GS-omega/kappa-Hxtx-Hv1 (VST-006340LC); tolfenpyrad; Capsicum oleoresin extract, garlic oil, and soybean oil (Captiva); and Isaria fumosorosea were not directly harmful to O. insidiosus (80-100% adult survival). Likewise, the pesticides such as tolfenpyrad, Captiva, and I. fumosoroea were not directly harmful to D. coriaria (80-100% adult survival). D. coriaria was more sensitive to VST-006340LC (40% survival) than O. insidiosus (100% survival), whereas O. insidiosus was more sensitive to flupyradifurone (0% survival) than D. coriaria (80% and 40% survival for both rates tested, respectively). The pesticides pyrethrins, spinosad, flupyradifurone, and combinations of tolfenpyrad and Captiva were directly harmful (<50% adult survival) to both natural enemies. However, none of the pesticides tested affected the ability of O. insidiosus adults to feed on western flower thrips adults.
In a recent Current Biology paper , we reported the oldest, morphologically specialized, and obligate termitophiles, Cretotrichopsenius burmiticus (Figure 1, left), from mid-Cretaceous Burmese amber, about 99 million years old. Cretotrichopsenius, belonging to the obligately termitophilous rove beetle tribe Trichopseniini, display the protective horseshoe-crab-shaped body typical of many extant termitophiles. However, the termitophilous lifestyle of Cretotrichopsenius is being questioned by Yamamoto et al. based on their representation of the termitophile-related features and premature and presumptive phylogenetic placement of Cretotrichopsenius within Trichopseniini. We stand by our interpretation that Cretotrichopsenius are obligate termitophiles, and Mesosymbion, a member of the largely free-living Mesoporini, are not necessarily termitophilous.