Insects comprise over half of all described animal species. Together with the Protura
(coneheads), Collembola (springtails) and Diplura (two-pronged bristletails), insects form …

Insects possess a cuticle that covers all tissues exposed to the outside world including the
body, the fore-and hindgut and the luminal side of the tracheae. The cuticle is a …

Integrated Principles of Zoology is a college text designed for an introductory course in
zoology. This thirteenth edition, as with previous editions, describes the diversity of animal …

Insects, the most diverse group of organisms, are nested within crustaceans, arguably the
most abundant group of marine animals. However, to date, no consensus has been reached …

Background Arthropods comprise the largest and most diverse phylum on Earth and play
vital roles in nearly every ecosystem. Their diversity stems in part from variations on a …

Candidate phyla radiation (CPR) bacteria separate phylogenetically from other bacteria, but
the organismal distribution of their protein families remains unclear. Here, we leveraged …

Insects are the most ecologically important multicellular heterotrophs in terrestrial systems.
They play critical roles in ecological food webs, remain devastating agricultural and medical …

Sex-determining mechanisms are diverse among animal lineages and can be broadly
divided into two major categories: genetic and environmental. In contrast to genetic sex …

An ambitious, yet fundamental goal for comparative biology is to understand the
evolutionary relationships for all of life. However, many important taxonomic groups have …

Background Land plants (embryophytes) evolved from streptophyte green algae, a small
group of freshwater algae ranging from scaly, unicellular flagellates (Mesostigma) to …