An unexpected twist: Sperm cells coil to the right in land snails and to the left in song birds

In animals, cell polarity may initiate symmetry breaking very early in development, ultimately leading to whole-body asymmetry. Helical sperm cells, which occur in a variety of animal clades, are one class of cells that show clearly visible bilateral asymmetry. We used scanning-electron microscopy to study coiling direction in helical sperm cells in two groups of animals that have figured prominently in the sperm morphology literature, namely land snails, Stylommatophora (514 spermatozoa, from 27 individuals, belonging to 8 species and 4 families) and songbirds, Passeriformes (486 spermatozoa, from 26 individuals, belonging to 18 species and 8 families). We found that the snail sperm cells were consistently dextral (clockwise), whereas the bird sperm cells were consistently sinistral (counterclockwise). We discuss reasons why this apparent evolutionary conservatism of sperm cell chirality may or may not be related to whole-body asymmetry

Dextral and sinistral Amphidromus inversus (Gastropoda: Pulmonata: Camaenidae) produce dextral sperm

Coiling direction in pulmonate gastropods is determined by a single gene via a maternal effect, which causes cytoskeletal dynamics in the early embryo of dextral gastropods to be the mirror image of the same in sinistral ones. We note that pulmonate gastropod spermatids also go through a helical twisting during their maturation. Moreover, we suspect that the coiling direction of the helical elements of the spermatozoa may affect their behaviour in the female reproductive tract, giving rise to the possibility that sperm chirality plays a role in the maintenance of whole-body chiral dimorphism in the tropical arboreal gastropod Amphidromus inversus (Müller, 1774). For these reasons, we investigated whether there is a relationship between a gastropod’s body chirality and the chirality of the spermatozoa it produces. We found that spermatozoa in A. inversus are always dextrally coiled, regardless of the coiling direction of the animal itself. However, a partial review of the literature on sperm morphology in the Pulmonata revealed that chiral dimorphism does exist in certain species, apparently without any relationship with the coiling direction of the body. Though our study shows that body and sperm chirality follows independent developmental pathways, it gives rise to several questions that may be relevant to the understanding of the chirality of spermatid ultrastructure and spermatozoan motility and sexual selection

Corrigendum to “Identification skills in biodiversity professionals and laypeople:A gap in species literacy” [Biol. Conserv. 238, October 2019, 108202]

In Fig. 3, because of an error in the R-script, the distribution of species literacy scores of one of the three target groups (the general public) is incorrect: the distribution has shifted 5 score-points to the left. The R-script was altered to make the correct ‘Fig. 3’ (see below). The textual description and interpretation of this figure remain unaltered. The authors would like to apologise for any inconvenience caused. The new Fig. 3: [Figure presented

A molecular and conchological dissection of the “scaly” Georissa of Malaysian Borneo (Gastropoda, Neritimorpha, Hydrocenidae)

The Bornean hydrocenids have so far been understudied compared to other non-pulmonate snails in this region. In the present study, we review a first group of minute land snail species belonging to the genus Georissa (Gastropoda, Hydrocenidae) from Malaysian Borneo. This group is restricted to the species with conspicuous scale-like sculpture on the shell. Based on materials from recent fieldwork, museums, and personal collections, Malaysian Borneo hydrocenids are more complex and diverse in shell characters than previously anticipated. Here, a molecular, conchological, and biogeographic study of this “scaly group” is presented. We recognise 13 species of which six are new to science, namely Georissa anyiensis sp. n., Georissa muluensis sp. n., Georissa bauensis sp. n., Georissa silaburensis sp. n., Georissa kinabatanganensis sp. n., and Georissa sepulutensis sp. n.NaturalisAnimal science

An observation on the ecology and behaviour of Metallyticus splendidus on a dead dipterocarp tree in Sabah, Malaysia (Mantodea, Metallyticidae)

Metallyticus is a genus of rare mantids, occurring mostly in SouthEast Asia. Five species have been described. However, their ecology and behaviour remain virtually unknown. In this study, we describe a small population of Metallyticus splendidus Westwood, 1889 on a dead dipterocarp tree standing in disturbed tropical rainforest around Danau Girang Field Centre, Sabah, Malaysia. At dawn, in the afternoon and at night, four individuals, two adults and two nymphs, were monitored. Our findings confirm earlier behavioural observations: they hold their bodies flat when running. We did not observe any lurking behaviour: the mantids were walking fast across the tree stem and in tree holes. M. splendidus was found at dawn, in the afternoon, and at night only on this single dead tree in a plot of 50 X 50 m. This suggests that M. splendidus is day and night-active and that its habitat is restricted to dead standing trees. We failed to find other individuals on other dead as well as living trees. Our findings show that the habitat of M. splendidus could be restricted to large dead trees, giving novel insights into the ecology of Metallyticidae.Microbial Biotechnolog

The effects of COVID-19 litter on animal life

During the COVID-19 pandemic, Personal Protective Equipment (PPE) is massively used, resulting in a new wave of litter: protective face masks and gloves. Here we present the first case of a fish entrapped in a medical glove, encountered during a canal clean-up in Leiden, The Netherlands. We also report the first cases of birds using medical face masks as nesting material, which were also found in the Dutch canals. To place these new findings in context, we collected online reported interactions of animals with PPE litter, since the start of the pandemic. This resulted in the first overview of cases of entanglement, entrapment and ingestion of COVID-19 litter by animals and the use of it as nesting material. We signal COVID-19 litter as a new threat to animal life as the materials designed to keep us safe are actually harming animals around us. To understand the full scale of this problem, we welcome anyone to contribute to our overview by submitting their observations online at www.covidlitter.com. To further prevent PPE litter, it is recommended that, when possible, reusable alternatives are used.Environmental Biolog

The complete mitogenome of Cylindrus obtusus (Helicidae, Ariantinae) using Illumina next generation sequencing

Animal science

Imperfect and askew: A review of asymmetric genitalia in araneomorph spiders (Araneae: Araneomorphae)

Bilateral asymmetry in the genitalia is a rare but widely dispersed phenomenon in the animal tree of life. In arthropods, occurrences vary greatly from one group to another and there seems to be no common explanation for all the independent origins. In spiders, genital asymmetry appears to be especially rare. Most known species show almost perfectly symmetrical genitals with the right and left sides being mirror images of each other. However, some examples of asymmetric genitalia have been studied and many other reports are scattered in the taxonomic literature. Based on a broad literature survey, we found several species in thirteen families with evidence of genital asymmetry, mostly expressed only in females. Our review suggests that spider genital asymmetries, although rare, are more common than previously thought and taxonomic descriptions and illustrations are a useful but not entirely reliable tool for studying them. Here we also report on directional asymmetry in the liocranid spider Teutamus politus, the first known case of morphologically asymmetric male genitals in Entelegynae spiders. Generalities, evolution and categorization of asymmetry in spiders are further discussed.Animal science