Fifty million years of beetle evolution along the Antarctic Polar Front.

Global cooling and glacial-interglacial cycles since Antarctica's isolation have been responsible for the diversification of the region's marine fauna. By contrast, these same Earth system processes are thought to have played little role terrestrially, other than driving widespread extinctions. Here, we show that on islands along the Antarctic Polar Front, paleoclimatic processes have been key to diversification of one of the world's most geographically isolated and unique groups of herbivorous beetles-Ectemnorhinini weevils.

Spotlight on the invasion of a carabid beetle on an oceanic island over a 105-year period.

The flightless beetle Merizodus soledadinus, native to the Falkland Islands and southern South America, was introduced to the sub-Antarctic Kerguelen Islands in the early Twentieth Century. Using available literature data, in addition to collecting more than 2000 new survey (presence/absence) records of M. soledadinus over the 1991-2018 period, we confirmed the best estimate of the introduction date of M.

Transdisciplinary Bioblitz: Rapid biotic and abiotic inventory allows studying environmental changes over 60 years at the Biological Field Station of Paimpont (Brittany, France) and opens new interdisciplinary research opportunities.

Background: The Biological Field Station of Paimpont (Station Biologique de Paimpont, SBP), owned by the University of Rennes and located in the Brocéliande Forest of Brittany (France), has been hosting student scientific research and field trips during the last 60 years. The study area of the SBP is a landscape mosaic of 17 ha composed of gorse moors, forests, prairies, ponds and creeks. Land use has evolved over time.

Studies on chill coma recovery in the ladybird, Harmonia axyridis: Ontogenetic profile, effect of repeated cold exposures, and capacity to predict winter survival.

The harlequin ladybird, Harmonia axyridis, is one of the most successful invasive insect species worldwide. We investigated whether (i) chill coma recovery time (CCRt) changes during the ontogenetic development of this species, (ii) CCRt varies in response to repeated cold shocks, and (iii) CCRt could be a good predictor of winter survival ability in adults. CCRt decreased during larval development, the lowest CCRt values were observed in teneral adults (one and four days old), and significantly higher values were observed for older adults (16 and 32 days old).

Insects in fluctuating thermal environments.

All climate change scenarios predict an increase in both global temperature means and the magnitude of seasonal and diel temperature variation. The nonlinear relationship between temperature and biological processes means that fluctuating temperatures lead to physiological, life history, and ecological consequences for ectothermic insects that diverge from those predicted from constant temperatures. Fluctuating temperatures that remain within permissive temperature ranges generally improve performance.

Well wrapped eggs: effects of egg shell structure on heat resistance and hatchling mass in the invasive land snail Cornu aspersum.

In ectotherms, the temperature changes that accompany climate shifts, microhabitat changes, and species range extensions can have profound effects on the performance of organisms. The aim of this laboratory study on the terrestrial invasive gastropod Cornu aspersum was to investigate the effect of dietary calcium source on egg shell structure and heat resistance of eggs in two populations from different climatic regions of France (Western Atlantic and Mediterranean). To date no literature is known about heat stress in calcified ectothermic eggs while exposed to heat peaks using fluctuating thermal regimes and optimal humidity.

Evolution of metabolic rate in a parasitic wasp: the role of limitation in intrinsic resources.

Metabolic rate, a physiological trait closely related to fitness traits, is expected to evolve in response to two main environmental variables: (1) climate, low metabolic rates being found in dry and hot regions when comparing populations originating from different climates in a common garden experiment and (2) resource limitations, low metabolic rates being selected when resources are limited. The main goal of this study was to investigate if differences in intrinsic resource limitations may have disrupted the expected evolution of metabolic rate in response to climate in a parasitic wasp. We compared CO(2) production of females from 4 populations of a Drosophila parasitoid, Leptopilina boulardi, as an estimate of their metabolic rate.

Variation in amine composition in plant species: how it integrates macroevolutionary and environmental signals.

Premise Of The Study: While plants show lineage-specific differences in metabolite composition, plant metabolites are also known to vary in response to the environment. The extent to which these different determinants of metabolite composition are mutually independent and recognizable is unknown. Moreover, the extent to which the metabolome can reconcile evolutionary constraint with the needs of the plant for rapid environmental response is unknown.

Temperature and parasitism by Asobara tabida (Hymenoptera: Braconidae) influence larval pupation behaviour in two Drosophila species.

In holometabolous insects, pupation site selection behaviour has large consequences for survival. Here, we investigated the combined effects of temperature and parasitism by the parasitoid Asobara tabida on larval pupation behaviour in two of its main Drosophila sp. hosts differing in their climate origin.

Overwintering strategy of two weevils infesting three gorse species: when cold hardiness meets plant-insect interactions.

The cold hardiness of two closely related weevil species, Exapion ulicis and E. lemovicinum was studied in relation to their life cycles. These two seed-eating weevils reproduce on Ulex plant species with different fruiting phenologies.

Influence of temperature acclimation and gut content on the supercooling ability of the land snail Cornu aspersum.

The invasive land snail Cornu aspersum possesses a low ability to supercool (c. -5 degrees C in winter) and survives only minimal ice formation in its body fluids, what may limit its expansion to colder environments. In the present study, we investigated the influence of acclimation and starvation on its supercooling ability.

Does fluctuating thermal regime trigger free amino acid production in the parasitic wasp Aphidius colemani (Hymenoptera: Aphidiinae)?

When stressful cold-exposure is interrupted by short warm intervals, physiological recovery is possible, and this improves markedly the survival of insects. Fluctuating thermal regime (FTR) may act as a cue triggering the initiation of a metabolic response involving synthesis of cryoprotective compounds, such as free amino acids (FAA). Since specific changes in FAA levels can provide a good indication of the overall response of an organism to stressful conditions, we investigated temporal changes in FAA body contents of the parasitoid Aphidius colemani Viereck during exposure to FTR (4 degrees C: 20 degrees C for 22 h: 2 h per day) versus constant low temperature (4 degrees C).

Supercooling ability is surprisingly invariable in eggs of the land snail Cantareus aspersus.

From an ontogenetic point of view, invertebrate eggs are generally the most freezing intolerant stage of a species. Development state, water content and acclimation may affect their supercooling ability. In this study, we measured fresh mass, water content and temperature of crystallisation (T(c)) of eggs of the edible land snail Cantareus aspersus, depending on its form ("aspersa"vs.

Antennal structure of male and female Aphidius rhopalosiphi DeStefani-Peres (Hymenoptera:Braconidae): description and morphological alterations after cold storage or heat exposure.

Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. But despite knowing the importance of sensory organs in their behavior, their antennal structure has never been described. We describe here the types and distribution of antennal sensilla in Aphidius rhopalosiphi, a larval parasitoid of several aphid species and observe how this antennal structure is modified after cold storage or heat exposure.

Freezing or supercooling: how does an aquatic subterranean crustacean survive exposures at subzero temperatures?

Crystallization temperature (T(c)), resistance to inoculative freezing (IF), ice contents, bound water, protein and glycogen body contents were measured in the aquatic subterranean crustacean Niphargus rhenorhodanensis and in the morphologically close surface-dwelling aquatic crustacean Gammarus fossarum, both acclimated at 12 degrees C, 3 degrees C and -2 degrees C. Cold acclimation induced an increase in the T(c) values in both species but no survival was observed after thawing. However, after inoculation at high sub-zero temperatures, cold-acclimated N.

Impact of extreme temperatures on parasitoids in a climate change perspective.

Parasitoids depend on a series of adaptations to the ecology and physiology of their hosts and host plants for survival and are thus likely highly susceptible to changes in environmental conditions. We analyze the effects of global warming and extreme temperatures on the life-history traits of parasitoids and interactions with their hosts. Adaptations of parasitoids to low temperatures are similar to those of most ectotherms, but these adaptations are constrained by the responses of their hosts.

Metabolic responses to cold in subterranean crustaceans.

Changes in polyol, sugar and free amino acid (FAA) body contents were investigated in the aquatic, subterranean (i.e. hypogean) crustaceans Niphargus rhenorhodanensis and Niphargus virei and in a morphologically close aquatic, surface-dwelling (i.

Behavioural, ventilatory and respiratory responses of epigean and hypogean crustaceans to different temperatures.

Impact of temperature (from -2 to 28 degrees C) on survival, oxygen consumption, locomotory and ventilatory activities was measured in two aquatic subterranean crustaceans (Niphargus rhenorhodanensis and Niphargus virei) and in a morphologically close surface-dwelling crustacean (Gammarus fossarum). The hypogean N. virei presented all characteristics of a stenothermal organism: it showed small thermal plasticity and optimised its performance on a narrow range of temperature.

Supercooling ability in two populations of the land snail Helix pomatia (Gastropoda: Helicidae) and ice-nucleating activity of gut bacteria.

The land snail Helix pomatia (Gastropoda: Helicidae) is widely distributed in Northern and Central Europe where it may experience subzero temperatures during winter months. Its supercooling ability was studied in two populations of H. pomatia.

Cold hardiness abilities vary with the size of the land snail Cornu aspersum.

The land snail Cornu aspersum (syn. Helix aspersa) living in Brittany (France) can be considered partially freezing tolerant as it possesses a low ability to supercool and a limited capacity to bear freezing of its body tissues. The absence of a marked cold hardiness strategy permits the emphasis of the role of parameters such as individual size or water mass (W(M)) contained by the organism.

Evolution of freezing susceptibility and freezing tolerance in terrestrial arthropods.

Arthropods have evolved various adaptations to survive adverse seasons and it has long been discussed why some arthropods are freezing-susceptible and some are freezing-tolerant. However, which mode of frost resistance came first during the course of evolution? A commonly held opinion is that no choice of strategy has been offered in evolution, because each species of arthropod may have its own evolutionary and natural history, leading to cold-hardiness. Freezing tolerance is more frequent in holometabolous insect orders and partially used by certain vertebrates, like some terrestrially hibernating amphibians and reptiles.

Effects of a freezing event during hibernation on further survival, reproduction and growth in the partially freezing tolerant land snail Helix aspersa muller (Gastropoda: helicidae).

Tolerance of ectothermic animals to freezing is often estimated by assessing survival a few days after the treatment. However, in the long term, ice formation in the body tissues can affect survival, as well as reproductive capability and growth. The land snail Helix aspersa survives only short durations with ice in its tissues, to a lethal limit of 40 to 60 % of its body water frozen.

The effect of antibiotic treatment on the supercooling ability of the land snail Helix aspersa (Gastropoda: Pulmonata).

The land snail Helix aspersa is a partially freezing tolerant species whose supercooling ability is limited to ca. -3 to -5 degrees C. One hundred adult snails were subjected to the following two experimental conditions: (i) a starved group, provided with water; (ii) an antibiotic-treated group that was provided with a solution containing a mixture of two antibiotics.