Comparative analysis of chromosome numbers and sex chromosome systems in Paraneoptera (Insecta)

This article is part (the 4th article) of the themed issue (a monograph) “Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera”. The purpose of this article is to consider chromosome structure and evolution, chromosome numbers and sex chromosome systems, which all together constitute the chromosomal basis of reproduction and are essential for reproductive success. We are based on our own observations and literature data available for all major lineages of Paraneoptera including Zoraptera (angel insects), Copeognatha (=Psocoptera; bark lice), Parasita (=Phthiraptera s. str; true lice), Thysanoptera (thrips), Homoptera (scale insects, aphids, jumping plant-lice, whiteflies, and true hoppers), Heteroptera (true bugs), and Coleorrhyncha (moss bugs). Terminology, nomenclature, classification, and the study methods are given in the first paper of the issue (Gavrilov-Zimin et al. 2021).

It’s time to mate: population-level plasticity of wild boar reproductive timing and synchrony in a changing environment

On a population-level, individual plasticity in reproductive phenology can provoke either anticipations or delays in the average reproductive timing in response to environmental changes. However, a rigid reliance on photoperiodism can constraint such plastic responses in populations inhabiting temperate latitudes. The regulation of breeding season length may represent a further tool for populations facing changing environments. Nonetheless, this skill was reported only for equatorial, non-photoperiodic populations. Our goal was to evaluate whether species living in temperate regions and relying on photoperiodism to trigger their reproduction may also be able to regulate breeding season length. During 10 years, we collected 2,500 female reproductive traits of a mammal model species (wild boar Sus scrofa) and applied a novel analytical approach to reproductive patterns in order to observe population-level variations of reproductive timing and synchrony under different weather and resources availability conditions. Under favorable conditions, breeding seasons were anticipated and population synchrony increased (i.e., shorter breeding seasons). Conversely, poor conditions induced delayed and less synchronous (i.e., longer) breeding seasons. The potential to regulate breeding season length depending on environmental conditions may entail a high resilience of the population reproductive patterns against environmental changes, as highlighted by the fact that almost all mature females were reproductive every year.

Reproductive strategies in vent shrimps shaped by feeding ecology with intriguing seasonality unlinked to surface productivity

Variations in reproductive patterns according to feeding strategies or food supply have been recognized in many animals from various ecosystems. Despite an unusual trophic structure, these relationships remain largely under-studied in chemosynthetic ecosystems. Here, we use Rimicaris shrimps as a study case to explore relations between reproduction, diets and food supply in these environments. For that, we compiled data on presence of reproductive individuals from the past 35 years and compared reproductive outputs of three shrimps differing by their diets and regions. We report distinct reproductive patterns between Rimicaris species according to their trophic regime regardless of variations related to body size. Besides, we observed a reproductive period mostly between January and early April whatever the region. Intriguingly, this periodicity does not correspond to seasonal variations with presence of ovigerous females during either boreal winter or austral summer. These observations contrast with the long-standing paradigm in deep-sea species for which periodic reproductive patterns have always been attributed to seasonal variations of photosynthetic production sinking from surface. Our results suggest the presence of intrinsic basis for biological rhythms in the deep sea, and bring to light the importance of having year-round observations in order to understand life history of vent animals.

Introduction to the study of chromosomal and reproductive patterns in Paraneoptera

This paper opens the themed issue (a monograph) “Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera”, prepared by a Russian-Bulgarian research team on the basis of long-term collaborative studies. In this first part of the issue, we provide the basic introductory information, describe the material involved and the methods applied, and give terminology and nomenclature of used taxonomic names.

An Indo-Pacific coral spawning database

The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology.

Demographic trends and reproductive patterns in the northern hairy-nosed wombat (Lasiorhinus krefftii) at Epping Forest National Park (Scientific), central Queensland

The critically endangered northern hairy-nosed wombat (Lasiorhinus krefftii) currently exists at only two locations in Queensland. Management, research and monitoring of the species at the main Epping Forest National Park (Scientific) population has occurred over the last four decades using a variety of tools, with the most complete dataset being provided by burrow activity monitoring over that period. Following a series of trap-based surveys in the 1980s and 1990s, wombat monitoring has employed DNA profiling of hairs collected remotely on sticky tape set at burrow entrances (since 2000), and passive infrared (PIR) cameras (since 2011). These techniques have produced a wealth of new information on the species. Using this new information, we aim to: (1) summarise the available demographic data and present new estimates using novel techniques for L. krefftii at Epping Forest NP; and (2) characterise reproductive patterns and their relationship with environmental factors for L. krefftii at Epping Forest NP. We find an ongoing increase in the population size at Epping Forest National Park, supported by healthy levels of reproduction despite periods of poor environmental conditions, notwithstanding the finding that cumulative monthly rainfall six months prior to sampling influenced birth rates. This trend suggests that the population will likely reach carrying capacity in the near future. It is timely to harvest the population to provide founders to a new site to establish an additional population, which will also reduce the risk of extinction and help secure the future of the species.

Edge creation changes the timing and intensity of phenological reproductive patterns and species activities in forest tree communities

Environmental characteristics are among the most important triggers and regulators of plant phenophases, so that the abiotic and biotic changes driven by habitat loss and fragmentation can result in alterations of plant phenological patterns. We investigated whether forest edge and interior have differences in phenological pattern of tree communities. We followed the reproductive phenologies of tree communities in seven forest fragments on a monthly basis for two years (in 200 m² edge and interior plots per fragment). We sampled a total of 0.28 ha of anthropic forest fragments, comprising 313 trees (180 in edge, 133 in interior) belonging to 103 species and 34 families. Our results evidenced reproductive phenological changes between edge and interior tree communities, with: (i) phenological activities differing temporally between the two habitats (edge and forest interior) in all tree communities; (ii) greater phenological intensity at the forest edge than in the forest interior among tree species common to both habitats; (iii) more tree species showed phenological activity at the forest edge in 2010 and interior in 2011, when considering only those exclusive to each habitat. Habitat fragmentation can therefore alter microenvironmental characteristics and influence biologic processes, including the reproductive phenologies of trees, through edge formation.