A Novel Power-Amplified Jumping Behavior in Larval Beetles (Coleoptera: Laemophloeidae)

Larval insects use many methods for locomotion. Here we describe a previously unknown jumping behavior in a group of beetle larvae (Coleoptera: Laemophloeidae). We analyze and describe this behavior in Laemophloeus biguttatus and provide information on similar observations for another laemophloeid species, Placonotus testaceus. Laemophloeus biguttatus larvae prelude jumps by arching their body while gripping the substrate with their legs over a period of 0.22 ± 0.17s. This is followed by a rapid ventral curling of the body after the larvae releases its grip that launches them into the air. Larvae reached takeoff velocities of 0.47 ± 0.15 m s-1 and traveled 11.2 ± 2.8 mm (1.98 ± 0.8 body lengths) horizontally and 7.9 ± 4.3 mm (1.5 ± 0.9 body lengths) vertically during their jumps. Conservative estimates of power output revealed that not all jumps can be explained by direct muscle power alone, suggesting Laemophloeus biguttatus uses a latch-mediated spring actuation mechanism (LaMSA) in which interaction between the larvae’s legs and the substrate serves as the latch. MicroCT scans and SEM imaging of larvae did not reveal any notable modifications that would aid in jumping. Although more in-depth experiments could not be performed to test hypotheses on the function of these jumps, we posit that this behavior is used for rapid locomotion which is energetically more efficient than crawling the same distance to disperse from their ephemeral habitat. We also summarize and discuss jumping behaviors among insect larvae for additional context of this behavior in laemophloeid beetles.

Progress on Research Regarding Ecology and Biodiversity of Coastal Fisheries and Nektonic Species and Their Habitats within Coastal Landscapes

This Special Issue aims to highlight the new research and significant advances in our understanding of links between coastal habitat quality/quantity/diversity and the diversity of fisheries species and other mobile aquatic species (hereafter nekton) that use them within coastal landscapes. This topic is quite diverse owing to the myriad of habitat types found in coastal marine waters and the variety of life history strategies fisheries species and nekton use in these environments. Thus, we focus our mini-review on five selective but relevant topics, habitat templates, essential fish habitat, habitat mosaics/habitat connectivity, transitory/ephemeral habitat, and the emerging/maturing approaches to the study of fish-habitat systems as a roadmap to its development. We have highlighted selected important contributions in the progress made on each topic to better identify and quantify landscape scale interactions between living biota and structured habitats set within a dynamic landscape.

Environmental risk assessment of veterinary parasiticides used in cattle

All veterinary medicines have to undergo a rigorous environmental risk assessment before gaining a marketing authorisation; post-marketing pharmacovigilance ensures constant surveillance for any environmental impacts that had not been anticipated from earlier research. Products are labelled to reflect any potential risk points. Despite these procedures, some compounds, notably parasiticides of the macrocyclic lactone class that are used in large animal practice, have gained a reputation among some scientists, the general public and the media for having adverse effects on dung insect fauna and for causing delays in the degradation of faeces on pasture. While the toxicity of faecal residues of insecticides to non-target insect fauna, when measured under controlled conditions in short-term experiments is indisputable, the consequences of such activity at ecological scales are much less well defined. Dung provides an ephemeral habitat for an enormous array of macro- and micro-invertebrates, fungi and bacteria, whose composition changes as pats age and disintegrate. Perturbations to such complex systems inevitably have a variety of outcomes and this is reflected in field trials, which can produce conflicting results. This article summarises pertinent aspects of the underlying biology and ecology of the bovine faecal pat and the evidence for significant impact of veterinary medication.

Plagues of Desert Locusts: Very Low Invasion Risk to China

Recently, the most serious upsurge of the desert locust (Schistocerca gregaria) in the last 25 years is spreading across eastern Africa and southwestern Asia. Parts of the desert locust ‘invasion area’, namely the northern border areas of Pakistan and India, are very close to China, and whether locust swarms will invade China is of wide concern. To answer this question, we identified areas of potentially suitable habitat for the desert locust within China based on historical precipitation and temperature data, and found that parts of Xinjiang and Inner Mongolia provinces could provide ephemeral habitat in summer, but these places are remote from any other desert locust breeding areas. New generation adults of the desert locust in Pakistan and India present since April led to swarms spreading into the Indo-Pakistan border region in June, and so we examined historical wind data for this period. Our results showed that winds at the altitude of locust swarm flight blew eastward during April–June, but the wind speeds were quite slow and would not facilitate desert locust eastward migration over large distances. Simulated trajectories of desert locust swarms undertaking 10-day migrations mostly ended within India. The most easterly point of these trajectories just reached eastern India, and this is very close to the eastern border of the invasion area of desert locusts described in previous studies. Overall, the risk that the desert locust will invade China is very low.

Seed germination of mudflat species responds differently to prior exposure to hypoxic (flooded) environments

Mudflats are exposed for short periods after flood water drawdown. They support fast-growing annual herbs with a ruderal strategy. To optimize their recruitment success, seeds of mudflat species germinate better under fluctuating temperatures, full illumination and aerobic environments that indicate the presence of optimal (non-flooded) conditions for plant growth and development. Here, we hypothesize that prior exposure of mudflat seeds to hypoxic (flooded) environment interferes with the germination process and results in more vigorous germination once aerobic conditions are regained. To test this hypothesis, seeds of five mudflat species were incubated in both aerobic and hypoxic environments at four (14/6, 22/14, 22/22 and 30/22°C) temperature regimes, reflecting different (seasonal) conditions when drawdowns may occur. All species responded positively to four temperature regimes; however, moderate 22/14 and 22/22°C temperatures were optimum for high percentages and rates (speed) of seed germination. Since seeds of four species germinated exclusively under aerobic conditions, they were moved from hypoxic to aerobic conditions. Prior exposure of seeds to hypoxic environment facilitated high percentages, rates and synchronization of germination of Limosella aquatica, Peplis portula and Samolus valerandi seeds compared to incubation under strict aerobic conditions. However, prior exposure to hypoxic environment induced secondary dormancy in non-dormant seeds of Hypericum humifusum but broke dormancy in Lythrum hyssopifolia seeds that otherwise required cold stratification to overcome physiological dormancy. All species that have a narrow ecological niche (strictly occurring in mudflat habitats) showed positive responses to prior exposure to hypoxic environments. In contrast, H. humifusum that has a wide ecological niche (from mudflats to moist sandy grasslands) showed a negative response. We conclude that the hypoxic environment may strongly affect seed germination behaviour once the aerobic environment is regained. The most striking effect is the acceleration of the germination process and, therefore, life cycle supporting the survival in an ephemeral habitat.

Plagues of Desert Locust: No invasion risk to China

Recently, the most serious upsurge of desert locust (Schistocerca gregaria) in the last 25 years is spreading across eastern Africa and southwestern Asia. Parts of the desert locust ‘invasion area’, namely the northern border areas of Pakistan and India are very close to China, and whether locust swarms will invade China is of wide concern. To answer this question, we identified areas of potentially suitable habitat for the desert locust within China based on historical precipitation and temperature data, and found that parts of Xinjiang and Inner Mongolia provinces could provide ephemeral habitat in summer, but these places are remote from any other desert locust breeding area. Presently, the desert locust populations in Pakistan and India are mature and have laid eggs, and are less likely to spread long distances. The next generation of adults will appear in April and May, and so we examined twenty years’ historical wind data (2000–2019) for this period. Our results showed that winds at the height of locust swarm flight blew eastward during April and May, but the wind speeds were quite slow and would not facilitate desert locust eastward migration over large distances. Furthermore, simulated trajectories of desert locust swarms with 10 days’ migration mostly ended within India. The most easterly point of these trajectories just reached eastern India, close to the border between India and Myanmar, and this is very close to the eastern border of the invasion area of desert locust described in previous studies. In conclusion, the risk that the desert locust will invade China is very low.

Mosaic heterochrony in neural progenitors sustains accelerated brain growth and neurogenesis in the juvenile killifish N. furzeri

SummaryWhile developmental mechanisms driving increase in brain size during vertebrate evolution are actively studied, we know less of evolutionary strategies allowing to boost brain growth speed. In zebrafish and other vertebrates studied to date, radial glia (RG) constitute the primary neurogenic progenitor population throughout life (Kriegstein and Alvarez-Buylla, 2009); thus, RG activity is a determining factor of growth speed. Here, we ask whether enhanced RG activity is the mechanism selected to drive explosive growth, in adaptation to an ephemeral habitat. In post-hatching larvae of the turquoise killifish, which display drastic developmental acceleration, we show that the dorsal telencephalon (pallium) grows three times faster than in zebrafish. Rather than resulting from enhanced RG activity, we demonstrate that pallial growth is the product of a second type of progenitors (that we term AP for apical progenitors) that actively sustains neurogenesis and germinal zone self-renewal. Intriguingly, AP appear to retain, at larval stages, features of early embryonic progenitors. In parallel, RG enter premature quiescence and express markers of astroglial function. Together, we propose that mosaic heterochrony within the neural progenitor population may permit rapid pallial growth by safeguarding both continued neurogenesis and astroglial function.

Nothobranchius furzeri, an 'instant' fish from an ephemeral habitat

The turquoise killifish, Nothobranchius furzeri, is a promising vertebrate model in ageing research and an emerging model organism in genomics, regenerative medicine, developmental biology and ecotoxicology. Its lifestyle is adapted to the ephemeral nature of shallow pools on the African savannah. Its rapid and short active life commences when rains fill the pool: fish hatch, grow rapidly and mature in as few as two weeks, and then reproduce daily until the pool dries out. Its embryos then become inactive, encased in the dry sediment and protected from the harsh environment until the rains return. This invertebrate-like life cycle (short active phase and long developmental arrest) combined with a vertebrate body plan provide the ideal attributes for a laboratory animal.