Microenvironmental variation in preassay rearing conditions can lead to anomalies in the measurement of life-history traits

2006 ◽  
Vol 85 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Sutirth Dey ◽  
Snigdhadip Dey ◽  
J. Mohan ◽  
Amitabh Joshi
2019 ◽  
Vol 19 (S2) ◽  
Author(s):  
Georgios A. Kyritsis ◽  
Antonios A. Augustinos ◽  
Ioannis Livadaras ◽  
Carlos Cáceres ◽  
Kostas Bourtzis ◽  
...  

Abstract Background Wolbachia pipientis is a widespread, obligatory intracellular and maternally inherited bacterium, that induces a wide range of reproductive alterations to its hosts. Cytoplasmic Incompatibility (CI) is causing embryonic lethality, the most common of them. Despite that Wolbachia-borne sterility has been proposed as an environmental friendly pest control method (Incompatible Insect Technique, IIT) since 1970s, the fact that Wolbachia modifies important fitness components of its hosts sets severe barriers to IIT implementation. Mass rearing of Mediterranean fruit fly, Ceratitis capitata (medfly), is highly optimized given that this pest is a model species regarding the implementation of another sterility based pest control method, the Sterile Insect Technique (SIT). We used the medfly-Wolbachia symbiotic association, as a model system, to study the effect of two different Wolbachia strains, on the life history traits of 2 C. capitata lines with different genomic background. Results Wolbachia effects are regulated by both C. capitata genetic background and the Wolbachia strain. Wolbachia infection reduces fertility rates in both C. capitata genetic backgrounds and shortens the pre-pupa developmental duration in the GSS strain. On the other hand, regardless of the strain of Wolbachia (wCer2, wCer4) infection does not affect either the sex ratio or the longevity of adults. wCer4 infection imposed a reduction in females’ fecundity but wCer2 did not. Male mating competitiveness, adults flight ability and longevity under water and food deprivation were affected by both the genetic background of medfly and the strain of Wolbachia (genotype by genotype interaction). Conclusion Wolbachia infection could alter important life history traits of mass-reared C. capitata lines and therefore the response of each genotype on the Wolbachia infection should be considered toward ensuring the productivity of the Wolbachia-infected insects under mass-rearing conditions.


2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Frank Hanson ◽  
Elizabeth Stanwyck ◽  
Alexander Bohorquez

Abstract Cultures of Manduca sexta Johanssen in our laboratory were found to have larvae with missing or deformed mouthparts or antennae. Hypothesizing that these developmental deformities were caused by crowded rearing conditions, we reared larvae in four different population densities and recorded the incidence (% of larvae affected) and types of chemoreceptor deformities. Results showed that the incidence of these deformities was directly proportional to larval population density. Deformities of the maxilla and palp were the most frequent, followed by those of the antenna, epipharynx and maxillary styloconica. Life history traits of larval mass, food consumption, and rate of development were inversely related to larval density for both normal and deformed larvae. We discuss possible causes and mechanisms of these deformities and of changes to life history traits.


2020 ◽  
Vol 650 ◽  
pp. 7-18 ◽  
Author(s):  
HW Fennie ◽  
S Sponaugle ◽  
EA Daly ◽  
RD Brodeur

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.


2020 ◽  
Vol 27 (4) ◽  
pp. 195-200
Author(s):  
Ufuk Bülbül ◽  
Halime Koç ◽  
Yasemin Odabaş ◽  
Ali İhsan Eroğlu ◽  
Muammer Kurnaz ◽  
...  

Age structure of the eastern spadefoot toad, Pelobates syriacus from the Kızılırmak Delta (Turkey) were assessed using phalangeal skeletochronology. Snout-vent length (SVL) ranged from 42.05 to 86.63 mm in males and 34.03 to 53.27 mm in females. Age of adults ranged from 2 to 8 years in males and 3 to 5 years in females. For both sexes, SVL was significantly correlated with age. Males and females of the toads reached maturity at 2 years of age.


Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.


2019 ◽  
Vol 144 (4) ◽  
pp. 389-411 ◽  
Author(s):  
Ramsés Djidjou‐Demasse ◽  
Gbenga J. Abiodun ◽  
Abiodun M. Adeola ◽  
Joel O. Botai

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