Search results for "Animal Science and Zoology"

Growth parameters and population structure of Aristeus antennatus (Decapoda, Penaeidae) in the south Tyrrhenian Sea (southern coast of Italy).

2011

Abstract The blue and red shrimp Aristeus antennatus (Risso, 1816) is one of the most important fishery resources in the Mediterranean Sea. Monthly samplings of blue and red shrimp from June 2006 to May 2007 were landed by the trawl fleet in two northwest Sicilian fishing harbours (San Vito Lo Capo and Terrasini). The carapace length (CL) frequency distribution of females ranged between 15.00 and 59.00 mm, whereas male CLs ranged between 17.00 and 34.00 mm. The estimated parameters of the Von Bertalanffy growth function (VBGF) for San Vito lo Capo females and males were: CL∞ = 65 mm, K = 0.58 y–1 and CL∞ = 41 mm, K = 0.71 y–1, respectively; while for Terrasini females and males these were:…

2019

Trade-offs have been shown to play an important role in the divergence of mating strategies and sexual ornamentation, but their importance in explaining warning signal diversity has received less attention. In aposematic organisms, allocation costs of producing the conspicuous warning signal pigmentation under nutritional stress could potentially trade-off with life-history traits and maintain variation in warning coloration. We studied this with an aposematic herbivore Arctia plantaginis (Arctiidae), whose larvae and adults show extensive variation in aposematic coloration. In larvae, less melanic coloration (i.e. larger orange patterns) produces a more efficient warning signal against pre…

Immense plasticity of timing of breeding in a sedentary forest passerine, Poecile palustris

2015

Numerous bird species have advanced their breeding seasons in response to climate warming. These changes were mostly brought about by phenotypic plasticity, i.e. flexible reactions of individual birds, rather than by microevolutionary change. Knowing the limits of plasticity is thus of paramount importance in any attempt to predict possible reactions of birds to climate warming. However, the breeding performance of the same individuals in contrasting environmental conditions, necessary to answer this question, is rarely observed. Here, we provide data on the flexibility in timing of egg-laying of individual marsh tit Poecile palustris females breeding in an extremely late (2013) and early (…

Selection for reproduction under short photoperiods changes diapause-associated traits and induces widespread genomic divergence.

2019

The work has been supported by the Academyof Finland to A.H. (project 267244) and Natural Environment Research Council (NERC) funding (NE/J020818/1 to M.G.R.; NE/L501852/1 to R.A.W.W.). The incidence of reproductive diapause is a critical aspect of life history in overwintering insects from temperate regions. Much has been learned about the timing, physiology and genetics of diapause in a range of insects, but how the multiple changes involved in this and other photoperiodically regulated traits are inter-related is not well understood. We performed quasinatural selection on reproduction under short photoperiods in a northern fly species, Drosophila montana, to trace the effects of photoper…

Spontaneous quantity discrimination of artificial flowers by foraging honeybees

2020

ABSTRACTMany animals need to process numerical and quantity information in order to survive. Spontaneous quantity discrimination allows differentiation between two or more quantities without reinforcement or prior training on any numerical task. It is useful for assessing food resources, aggressive interactions, predator avoidance and prey choice. Honeybees have previously demonstrated landmark counting, quantity matching, use of numerical rules, quantity discrimination and arithmetic, but have not been tested for spontaneous quantity discrimination. In bees, spontaneous quantity discrimination could be useful when assessing the quantity of flowers available in a patch and thus maximizing f…

Cercarial behaviour alters the consumer functional response of three‐spined sticklebacks

2020

This is the peer reviewed version of the following article: Born-Torrijos, A., Paterson, R., van Beest, G., Vyhlídalová, T., Henriksen, E.H., Knudsen, R., Kristoffersen, R., Amundsen, P.-A. & Soldánová, M. (2021). Cercarial behaviour alters the consumer functional response of three-spined sticklebacks. Journal of Animal Ecology, 90, 978-988, which has been published in final form at https://doi.org/10.1111/1365-2656.13427. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by st…

Impact of host nutritional status on infection dynamics and parasite virulence in a bird-malaria system.

2014

10 pages; International audience; Host resources can drive the optimal parasite exploitation strategy by offering a good or a poor environment to pathogens. Hosts living in resource-rich habitats might offer a favourable environment to developing parasites because they provide a wealth of resources. However, hosts living in resource-rich habitats might afford a higher investment into costly immune defences providing an effective barrier against infection. Understanding how parasites can adapt to hosts living in habitats of different quality is a major challenge in the light of the current human-driven environmental changes. We studied the role of nutritional resources as a source of phenoty…

Sensitive measure of prevalence and parasitaemia of haemosporidia from European blackbird (Turdus merula) populations: value of PCR-RFLP and quantita…

2006

8 pages; International audience; Haemosporidian parasites are common in birds in which they act as an important selective pressure. While most studies so far have focused on the effect of their prevalence on host life-history traits, no study has measured the effect of parasitaemia. We developed molecular methods to detect, identify and quantify haemosporidia in 2 natural populations of the Blackbird Turdus merula. Three different parasite genotypes were found - 1 Haemoproteus and 2 Plasmodium. A PCR-RFLP screening revealed that only approximately 3% of blackbirds were free of parasites, compared to the 34% of uninfected birds estimated by blood smear screening. A quantitative PCR (q-PCR) a…

Distinct protoconchs recognised in three of the larger Mediterranean Cerithium species (Caenogastropoda: Cerithiidae)

2017

The gastropod genus Cerithium includes several polymorphic species which are hardly distinguishable using a morphological approach based on teleoconch characters. Here we show that protoconch characters can be reliably used to identify the larger Mediterranean species (Cerithium alucastrum, C. repandum and C. vulgatum), and to assess their intraspecific variability. Based on a large amount of morphological data, we show that a multispiral, strongly sculptured protoconch (traditionally associated with C. vulgatum) is found in C. alucastrum. This species originated in the Pliocene. A multispiral, weakly sculptured protoconch, not observed previously, is reported for C. vulgatum. A paucispiral…

Bees increase oilseed rape yield under real field conditions

2018

prod 2018-210 EA GESTAD INRA; International audience; Oilseed rape (OSR, Brassica napus L.) is a common crop found in many European agricultural landscapes. It ispollinated by a wide variety of insects, but the reported contribution of pollinators to yield varies widely betweenstudies (from 0 to 50%). Moreover, such a contribution has seldom been estimated at the field scale in realfarming conditions. We analysed OSR yields in response to insect pollination; over four years, at two differentscales: farm fields and individual plants. We used both empirical and experimental approaches along a gradientof pollinator diversity and abundance. The empirical approach was based on farm surveys (151 …