Climate change is affecting biodiversity, but proximate drivers remain poorly understood. Here, we examine how experimental heatwaves impact on reproduction in an insect system. Male sensitivity to heat is recognised in endotherms, but ectotherms have received limited attention, despite comprising most of biodiversity and being more influenced by temperature variation. Using a flour beetle model system, we find that heatwave conditions (5 to 7 °C above optimum for 5 days) damaged male, but not female, reproduction. Heatwaves reduce male fertility and sperm competitiveness, and successive heatwaves almost sterilise males. Heatwaves reduce sperm production, viability, and migration through the female. Inseminated sperm in female storage are also damaged by heatwaves. Finally, we discover transgenerational impacts, with reduced reproductive potential and lifespan of offspring when fathered by males, or sperm, that had experienced heatwaves. This male reproductive damage under heatwave conditions provides one potential driver behind biodiversity declines and contractions through global warming.

The Tardigrada Register: a comprehensive online data repository for tardigrade taxonomy

In this paper we describe Macrobiotus paulinae, a new species of the hufelandi group from the Kenyan highlands. In addition to the traditional taxonomic description, aided with morphometrics as well as light and scanning microscopy imaging, we also provide nucleotide sequences of three nuclear (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial (COI) DNA fragment of the new species. The sequences allowed not only a more accurate description but also provided an independent verification of the taxonomic status of Ma. paulinae sp. nov. Such integrative approach requires a considerable number of individuals and eggs, which we have partially subsidised by employing an in vitro culture of the new species. Our analyses revealed that Ma. paulinae sp. nov. is most similar to Macrobiotus madegassus Maucci, 1993 and Macrobiotus modestus Pilato & Lisi, 2009, however it differs from these species, as well as from all other known species of the hufelandi group, by the presence of seven paired dorso-lateral patches of cuticular granulation and the presence of chorionic filaments growing out of terminal discs of egg processes. Macrobiotus paulinae sp. nov. is an example of a species with a miniaturised buccal apparatus (i.e. with reduced peribuccal lamellae and oral cavity armature, and stylet supports inserted on the buccal tube more anteriorly than in typical Ma. hufelandi group species), and it therefore resembles two recently described two-macroplacoided Minibiotus species: Mi. acadianus Meyer & Domingue, 2011 and Mi. julianae Meyer, 2012. The re-examination of the type material for these two species confirmed that they are equipped with peribuccal lamellae and therefore we transfer them to the genus Macrobiotus, specifically to the hufelandi group.

A laboratory strain identified as “Hypsibius dujardini” is one of the best studied tardigrade strains: it is widely used as a model organism in a variety of research projects, ranging from developmental and evolutionary biology through physiology and anatomy to astrobiology. Hypsibius dujardini, originally described from the Île-de-France by Doyère in the first half of the 19th century, is now the nominal species for the superfamily Hypsibioidea. The species was traditionally considered cosmopolitan despite the fact that insufficient, old and sometimes contradictory descriptions and records prevented adequate delineations of similar Hypsibius species. As a consequence, H. dujardini appeared to occur globally, from Norway to Samoa. In this paper, we provide the first integrated taxonomic redescription of H. dujardini. In addition to classic imaging by light microscopy and a comprehensive morphometric dataset, we present scanning electron photomicrographs, and DNA sequences for three nuclear markers (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial marker (COI) that are characterised by various mutation rates. The results of our study reveal that a commercially available strain that is maintained in many laboratories throughout the world, and assumed to represent H. dujardini sensu stricto, represents, in fact, a new species: H. exemplaris sp. nov. Redescribing the nominal taxon for Hypsibiidae, we also redefine the family and amend the definitions of the subfamily Hypsibiinae and the genus Hypsibius. Moreover, we transfer H. arcticus (Murray, 1907) and Hypsibius conifer Mihelčič, 1938 to the genus Ramazzottius since the species exhibit claws and eggs of the Ramazzottius type. Finally, we designate H. fuhrmanni as subjectively invalid because the extremely poor description precludes identifying neotype material.

Species of the Macrobiotus hufelandi group are one of the most often recorded tardigrades throughout the globe. For over a century M. hufelandi has been considered cosmopolitan but in recent decades numerous species of similar morphologies have been described from various continents, which suggests that what was originally defined as a single taxon is, in fact, a complex of species. The definition of the hufelandi group is subject to a long-standing discussion and in this paper we propose a refined set of characters that are hoped to elucidate the taxonomic status of the group. In order to aid interspecific comparisons, we also propose a unified nomenclature for the crucial morphological traits and clar