Burial has a unique effect on carrion fauna and this may affect the decomposition rate, consequently interfering with postmortem estimates. We surveyed the Coleoptera on buried rabbit carcasses ...between April 2008 and March 2009. The insects of forensic importance totaled 1,502 individuals, constituting 87.12% of the Coleoptera collected. The composition of the beetle community varied seasonally. Exposed carcasses lost weight much faster than buried ones. The weight lost by exposed cadavers in a week was greater than those carcasses buried for 10 wk. The temperature variations of the buried carcasses and the soil were around three times less variable than the environmental temperature. The proximity between the temperature variations of the soil and buried carcasses was because of the absence of larval masses. The results show differences in decomposition and faunal composition, demonstrating their relevance in the interpretation of cases with bodies in a similar situation.
The evolution and genomic basis of beetle diversity McKenna, Duane D.; Shin, Seunggwan; Ahrens, Dirk ...
Proceedings of the National Academy of Sciences - PNAS,
12/2019, Volume:
116, Issue:
49
Journal Article
Peer reviewed
Open access
The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, ...remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles—remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.
Significance Many suggest we are approaching a sixth mass extinction event, and yet estimates of how many species exist, and thus how many might become extinct, vary by as much as an order of ...magnitude. There are few statistically robust methods to estimate global species richness, and here we introduce several new methods, including one that builds on the observation that larger species are often described before smaller species. We combine these, giving equal weight to each, to provide mean global species estimates for the most speciose order, class, and phylum on Earth, beetles, insects, and arthropods (terrestrial). We attempt to aid conservation planning by broadening the range of methods used and bringing greater stability to global estimates for these taxa.
It has been suggested that we do not know within an order of magnitude the number of all species on Earth May RM (1988) Science 241(4872):1441â1449. Roughly 1.5 million valid species of all organisms have been named and described Costello MJ, Wilson S, Houlding B (2012) Syst Biol 61(5):871â883. Given Kingdom Animalia numerically dominates this list and virtually all terrestrial vertebrates have been described, the question of how many terrestrial species exist is all but reduced to one of how many arthropod species there are. With beetles alone accounting for about 40% of all described arthropod species, the truly pertinent question is how many beetle species exist. Here we present four new and independent estimates of beetle species richness, which produce a mean estimate of 1.5 million beetle species. We argue that the surprisingly narrow range (0.9â2.1 million) of these four autonomous estimatesâderived from host-specificity relationships, ratios with other taxa, plant:beetle ratios, and a completely novel body-size approachârepresents a major advance in honing in on the richness of this most significant taxon, and is thus of considerable importance to the debate on how many species exist. Using analogous approaches, we also produce independent estimates for all insects, mean: 5.5 million species (range 2.6â7.8 million), and for terrestrial arthropods, mean: 6.8 million species (range 5.9â7.8 million), which suggest that estimates for the worldâs insects and their relatives are narrowing considerably.
Small-scale soil scarification under canopies has been proposed to remove regeneration inhibitor plants that often dominate the understory in natural forests after selection logging. We studied the ...impacts of the small-scale soil scarification on carabid beetle assemblages in conifer-hardwood mixed forests in northern Japan. We sampled carabid beetles using pitfall traps in scarified sites and adjacent unscarified sites two and four years after scarification. Forest species made up 98% of the total catch with only a few individuals of non-forest species occurring in scarified sites. Species richness of forest species did not differ significantly between scarified and unscarified sites, whereas species richness of non-forest species was higher in scarified sites than in unscarified sites. Carabid species composition differed between scarified and unscarified sites in each of the two study years. Dissimilarity measures between scarified and adjacent unscarified sites were smaller after four years than after two years, indicating that differences in species composition associated with scarification declined during the study period. Some forest species were more abundant in scarified sites, whereas other forest species were more abundant in unscarified sites. Our results suggest that small-scale scarification may have a limited impact on carabid beetle diversity.
Flight speed is positively correlated with body size in animals
. However, miniature featherwing beetles can fly at speeds and accelerations of insects three times their size
. Here we show that this ...performance results from a reduced wing mass and a previously unknown type of wing-motion cycle. Our experiment combines three-dimensional reconstructions of morphology and kinematics in one of the smallest insects, the beetle Paratuposa placentis (body length 395 μm). The flapping bristled wings follow a pronounced figure-of-eight loop that consists of subperpendicular up and down strokes followed by claps at stroke reversals above and below the body. The elytra act as inertial brakes that prevent excessive body oscillation. Computational analyses suggest functional decomposition of the wingbeat cycle into two power half strokes, which produce a large upward force, and two down-dragging recovery half strokes. In contrast to heavier membranous wings, the motion of bristled wings of the same size requires little inertial power. Muscle mechanical power requirements thus remain positive throughout the wingbeat cycle, making elastic energy storage obsolete. These adaptations help to explain how extremely small insects have preserved good aerial performance during miniaturization, one of the factors of their evolutionary success.
The sex of adults of Phenolia (Lasiodites) picta (MacLeay) is distinguished by the morphology of the pygidium and the presence of a well sclerotized tergite VIII in males. These differences are ...visible under a binocular microscope at a low magnification (15×). As the difference between the sexes can be distinguished without killing specimens, it can be used to observe the specific behaviors of females and males and in ecological research.
Beetles represent almost one-fourth of all described species, and knowledge about their relationships and evolution adds to our understanding of biodiversity. We performed a comprehensive ...phylogenetic analysis of Coleoptera inferred from three genes and nearly 1900 species, representing more than 80% of the world's recognized beetle families. We defined basal relationships in the Polyphaga supergroup, which contains over 300,000 species, and established five families as the earliest branching lineages. By dating the phylogeny, we found that the success of beetles is explained neither by exceptional net diversification rates nor by a predominant role of herbivory and the Cretaceous rise of angiosperms. Instead, the pre-Cretaceous origin of more than 100 present-day lineages suggests that beetle species richness is due to high survival of lineages and sustained diversification in a variety of niches.
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