Search results for "Hatching"
showing 10 items of 98 documents
Direct and transgenerational effects of an experimental heatwave on early life stages in a freshwater snail
2019
1. Global climate change imposes a serious threat to natural populations of many species. Estimates of the effects of climate change‐mediated environmental stresses are, however, often based only on their direct effects on organisms, and neglect the potential transgenerational (e.g. maternal) effects. 2. We tested whether high temperature (i.e. an experimental heatwave), which is known to reduce the performance of adult Lymnaea stagnalis snails, affects the produced offspring (eggs and hatchlings) through maternal effects, and how strong these effects are compared with the effects of direct exposure of offspring to high temperature. We examined the effect of maternal thermal environment (15…
Henneguya zschokkei (Myxozoa) infection in cultured whitefish: Age-dependence, seasonality and distribution within host
2017
Abstract Whitefish ( Coregonus lavaretus ) is an important species for European fisheries and aquaculture. Recently, the myxosporean Henneguya zschokkei has been observed to infect the muscles of whitefish in fish farms. Plasmodia of H. zschokkei prevent marketing of the fillet and cause economic losses. The factors associated with occurrence of the parasite in fish farms have not been investigated previously. We studied age-dependence, seasonality, and within-host distribution of H. zschokkei plasmodia in farmed whitefish by examining a total of 1599 fish. Distribution of plasmodia within the fish was not uniform. When the fillet was divided into parts, the number of plasmodia was positive…
Trans-generational immune priming in the mealworm beetle protects eggs through pathogen-dependent mechanisms imposing no immediate fitness cost for t…
2018
8 pages; International audience; Immune-challenged mothers can improve their offspring immunity through trans-generational immune priming (TGIP). In insects, TGIP endows the offspring with lifetime immunity, including the eggs, which are likely exposed soon after maternal infection. Egg protection may rely on the transfer of maternal immune effectors to the egg or/and the induction of egg immune genes. These respective mechanisms are assumed to have early-life fitness costs of different magnitude for the offspring. We provide evidence in the mealworm beetle Tenebrio molitor that enhanced egg immunity following a maternal immune challenge is achieved by both of these mechanisms but in a path…
Come rain or come shine: environmental effects on the infective stages of Sparicotyle chrysophrii, a key pathogen in Mediterranean aquaculture
2018
Background Evidence concerning the environmental influence on monogenean transmission and infection processes is widely accepted, although only the effects of a limited number of abiotic factors on particular monogenean species have been explored. The current context of climate change calls for further research both on this subject, and also that concerning monogenean hosts, especially in aquaculture. Methods In this study, four experiments were used to assess the response of the infective stages of Sparicotyle chrysophrii, a pathogenic monogenean from gilthead sea bream (Sparus aurata) cultures in the Mediterranean, to variations of temperature (from 10 °C to 30 °C), pH (7.0 and 7.9), phot…
Maternal care provides antifungal protection to eggs in the European earwig
2014
Many insects raise their offspring on organic substrates or in the soil where microorganisms are abundant. Microbes may pose a serious threat to offspring development and survival by either decomposing food resources or directly infecting the offspring. Selection to cope with these effects may favor social defenses, for example, through forms of parental care that can limit or eliminate these threats to offspring fitness. In this study, we experimentally tested if maternal egg attendance in the European earwig Forficula auricularia has a function as a social defense against mold infection of eggs by manipulating exposure of eggs to mold spores and the presence of the mother in a fully facto…
Impacts of ambient temperature and clutch size on incubation behaviour onset in a female-only incubator songbird
2021
Ambient temperature is assumed to be the major cue used by passerines to synchronize their laying and hatching dates to the expected peak of prey availability. While laying eggs, females are still able to fine-tune their hatching date following increasing or decreasing patterns of ambient temperature, mostly via changes in incubation onse t. The onset of incubation behaviour in relation to the laying sequence could have later conse- quences for the duration of the incubation period and the extent of hatching asynchrony. Clutch size is also known to affect incubation patterns and might therefore condition potential responses to changing temperatures. In this study we assessed the association…
Variation in Great Tit Nest Mass and Composition and Its Breeding Consequences: A Comparative Study in four Mediterranean Habitats
2013
Bird nests are structures whose properties affect breeding performance. Thus, the vast majority of bird species build their own characteristic nests, selecting appropriate materials to do so. However, in habitats where the availability of "ideal" materials is low, some ability to use alternative ones would be necessary, even at the cost of having breeding success reduced. The Great Tit (Parus major) breeds under widely different environmental conditions. Its nests are althought to be composed mainly of moss, although very few studies have quantified nest composition. Our target here was describing Great Tit nest mass and composition in four different Mediterranean habitats, and exploring th…
Incubation and hatching periods in a Mediterranean Great Tit Parus major population
2014
Capsule The onset of incubation relative to clutch completion is highly variable in Great Tits Parus major, and has important consequences for the duration of the incubation and hatching periods.Aim To investigate when incubation starts relative to clutch completion, its effects on the length of the incubation and hatching periods, and which proximate factors affect all of these traits.Methods We used data from a Great Tit population in Eastern Spain collected over 15 years. Periodic visits to the nests (daily at some stages) allowed the determination of breeding parameters of interest. General linear models were used for analyses.Results On average, incubation started the day of laying of …
Limitation of Reproductive Success by Food Availability and Breeding Time in Pied Flycatchers
1998
Seasonal variation in reproductive success is a common phenomenon in many taxa. In birds, the costs and benefits associated with alternative breeding dates cause variation in clutch size, which is a main cause of seasonal decline in reproductive success. An immediate cause for this might be seasonal variation in the environment, or alternatively, but not mutually exclusively, date-independent differences in the parental/territory quality of early and late parents. The predictions of these hypotheses on seasonal reduction of reproductive success were tested by manipulating the hatching date and the amount of food during the nestling period of Pied Flycatchers (Ficedula hypoleuca). Delay in t…
Biological activity of Bacillus spp. evaluated on eggs and larvae of red palm weevil Rhynchophorus ferrugineus
2014
This study was conducted to characterize the Bacillus populations associated with dead Rhynchophorus ferrugineus, to develop a biological control for the red palm weevil. Dead adult beetles, collected throughout Sicily, were used for isolating internal and external spore forming bacteria (SFB) microbiota. The isolates, preliminarily allotted to the Bacillaceae family, were tested at 4 concentrations (103 to 106 CFU/mL) for their ability to inhibit hatching of eggs of R. ferrugineus and were used at 106 CFU/mL to monitor their insecticidal activity against 10 day-old larvae. Total amounts of SFB measured outside the skeleton and in the inners part of the beetles were 5.59-6.94 and 5.17-7.05 …