Search results for "Hatching"
showing 10 items of 98 documents
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…
Food supplementation reveals constraints and adaptability of egg quality in the magpie Pica pica
2015
Differences in the deposition of limited maternal resources to eggs can reflect the optimal allocation to manipulate offspring phenotype, or constraints caused by maternal condition. We examined multiple maternal substances transferred to eggs in the magpie Pica pica to test the hypothesis that certain substances represent constraint and some optimal allocation. We did this by supplementary feeding magpies prior to egg-laying and then comparing the effect of food on maternal substances in conjunction with laying order relative to a control group. Certain substances such as carotenoids, immunoglobulins and avidin responded positively to food supplementation, whereas others, such as testoste…
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 …
Effects of food abundance and early clutch predation on reproductive timing in a high Arctic shorebird exposed to advancements in arthropod abundance.
2016
12 pages; International audience; Climate change may influence the phenology of organisms unequally across trophic levels and thus lead to phenological mismatches between predators and prey. In cases where prey availability peaks before reproducing predators reach maximal prey demand, any negative fitness consequences would selectively favor resynchronization by earlier starts of the reproductive activities of the predators. At a study site in northeast Greenland, over a period of 17 years, the median emergence of the invertebrate prey of Sanderling Calidris alba advanced with 1.27 days per year. Yet, over the same period Sanderling did not advance hatching date. Thus, Sanderlings increasin…
Effects of Tributyltin(IV) Chloride Exposure on Larvae ofCiona intestinalis (Urochordata): An Ultrastructural Study
1996
The effects of tributyltin(IV) chloride (TBT chloride) have been tested on embryos of the ascidian Ciona intestinalis, at two different stages of development: (1) before hatching (coiled larval stage) and (2) 2 h after hatching (swimming larval stage). In vivo observations carried out with a light microscope showed that embryos at the coiled larval stage did not hatch following exposure to TBT chloride. Severe anomalies in the swimming larva, mainly concerning the morphology of the tail, which appeared twisted and squatter than in the controls, were observed. Such anomalies were also found at a functional level, i.e. contractile movements were poor so that the larvae appeared motionless. Ul…
Clutch size and egg volume in great tits (Parus major) increase under low intensity electromagnetic fields: a long-term field study.
2012
Exposure to electromagnetic fields (EMFs) can affect a wide range of biological processes, including reproduction, growth and development. Experiments aimed at investigating the biological effects of EMFs, focused on potential harmful effects on humans, have been mostly carried out in vitro or with animal models in laboratory conditions. By contrast, studies performed on wild animals are scarce. The effects of EMFs created by an electric power line on reproductive traits of a wild great tit (Parus major) population were explored by analysing data gathered during nine breeding seasons. EMF exposure significantly increased clutch size (7%) and egg volume (3%), implying a 10% increase in clutc…
Effects of the insect growth regulator cyromazine on the fecundity, fertility and offspring development of Mediterranean fruit fly,Ceratitis capitata…
1995
Addition of cyromazine to adult diet affected negatively the development of Ceratitis capitata Wied. (Dipt., Tephritidae) offspring. Five concentrations of cyromazine (0.00001 mg/ml, 0.01 mg/ml, 0.1 mg/ml, 1 mg/ml and 10 mg/ml) have been tested. A reduction of Mediterranean fruit fly populations has been found mainly due to the effects of fertility and larval development. At these concentrations, cyromazine does not affect Ceratitis capitata fecundity.
Modes, mechanisms and evidence of bet hedging in rotifer diapause traits
2016
In this contribution, we review our knowledge on bet-hedging strategies associated with rotifer diapause. First, we describe the ecological scenario under which bet hedging is likely to have evolved in three diapause-related traits in monogonont rotifer populations: (1) the timing of sex (because diapausing eggs are produced via sexual reproduction), (2) the sexual reproduction ratio (i.e. the fraction of sexually reproducing females) and (3) the timing of diapausing egg hatching. Then, we describe how to discriminate among bet-hedging modes and discuss which modes and mechanisms better fit the variability observed in these traits in rotifers. Finally, we evaluate the strength of the empiri…
Life span, dispersal and age of nesting Great Grey Owls (Strix nebulosa lapponica) in Sweden.
2016
3,073 Great Grey Owls were banded in Sweden in 1955–2012. 416 were controlled at least once (54.6%) or recovered dead (45.4%). Three birds banded as nestlings were recovered in their 17th calendar year. Most birds were recovered during first year of life. Only 4 females were controlled breeding as 2CY birds. 91.3% of birds controlled as first time breeders were at least 4CY. Birds banded as nestlings and recovered dead between September and July moved 100.8 km (mean) with a median distance of 64 km. Juveniles controlled alive moved 45.9 km (mean) with a median distance of 23 km during first year of life. Maximum natal dispersal was 650 km. Median natal dispersal for females was 40 km, betwe…
Disappearance of malachite green residues in fry of rainbow trout (Oncorhynchus mykiss) after treatment of eggs at the hatching stage
2009
Abstract The disappearance of malachite green (MG) residues was determined in fry of rainbow trout (Oncorhynchus mykiss) after six repeated treatments of the eggs at the hatching stage with MG oxalate at exposure levels of 1, 3 and 6 mg l− 1 for 30 min. Fry samples were taken from newly hatched fry (0 days post-hatch, d.p.h.) and at regular time intervals at 16, 31, 43, 57 and 96 d.p.h. The residues of MG and its major metabolite, leucomalachite green (LMG), were found to accumulate in the fry after MG treatments of eggs, with the highest residue levels being determined in the newly hatched fry. After exposures of 3 mg l− 1 MG, mean concentrations of 1170 ± 106 µg kg− 1 and 276 ± 38.6 µg kg…