Nutrition and Water Deprivation Negatively Impacts Adult Longevity of Lucilia eximia (Diptera: Calliphoridae)

Introduction: Forensic entomology is the utilization of arthropod science in legal practice. Blow flies (Diptera: Calliphoridae) are a prevalent family in medicolegal investigations due to their colonization of vertebrates, including living or deceased humans. Longevity of insects associated with legal investigations is an important life-history trait that could be useful in determining a minimum time of colonization (TOC) interval. Lucilia eximia (Wiedemann) (Diptera: Calliphoridae) is known to colonize remains and cause myiasis; however, this species is understudied. The purpose of this study was to investigate the longevity of L. eximia adults with and without resources. Methods: Lucilia eximia adults were placed in six different mesh cages at a 1:1 sex ratio, where flies in three cages were fed and provided water, while those in the remaining cages were not. Cages were placed in a walk-in incubator set to 24°C, 60% RH, and a 14:10 L:D. Mortality was recorded daily. Results:Males and females did not live significantly longer than each other within either treatment. Life span of adults provided resources was 58.41 ± 27.79 d, while deprived individuals lived 1.61 ± 0.49 d. Rate of mortality was nearly 6X greater for those deprived of food and water than those provided such resources. Conclusions: Access to food and water impacted adult longevity. Forensic entomologists could potentially estimate time since adult emergence based on mortality proportion of adults present in relation to environmental conditions and access to food in an enclosed environment (e.g., building). However, such a method will need to be validated.

Age-dependent genetic architecture underlines similar heritability of body size in sticklebacks

Heritable variation in traits under natural selection is a prerequisite for evolutionary response. While it is recognised that trait heritability may vary spatially and temporally depending under which environmental conditions traits are expressed, less is known about the possibility that genetic variance contributing to the expected selection response in a given trait may vary at different stages of ontogeny. Specifically, whether different loci underlie the expression of a trait throughout development - thus providing an additional source of variation for selection to act on - is unclear. Here we show that the heritability (h2) of body size, an important life history trait, remains constant across ontogeny in a stickleback fish. Nevertheless, both analyses of quantitative trait loci (QTL) and genetic correlations across ages show that different chromosomes/loci contribute to this heritability in different ontogenic time-points. This suggests that body size can respond to selection at different stages of ontogeny but that this response is determined by different loci at different points of development. Hence, this illustrates the notion that diverse genetic architectures may underline similar (expected) phenotypic outcomes, and that similar selection pressures may lead to genetically heterogeneous responses depending on what life stage selection is acting on.

A study on phenological traits of Abies pindrow (Royle) Spach. in the different sites of Garhwal Himalayas, India

Phenology, the timing of various events in a species life cycle, is an important life history trait for both plants and animals. Dharali site situated in the highest altitudinal range i.e. 2800-3300 m above msl and showed the initiation of all the phenological characteristics i.e. leaf fall, leaf emergence, appearance of male and female strobili, pollination, cone maturation and seed dispersal in advance as compared to all the other sites. The comparison of the two years phenological data in all the sites (Mundali, Bhukki, Dheoban, Dharali) showed that in the year 2013 early leaf emergence, prolonged cone maturity and early seed dispersal were observed. Rise in temperature and change in climate in mountainous regions has caused the tree line to advance to higher elevations as temperatures have increased over the past few decades. In addition to changing their spatial distributions, plants are also chang-ing their temporal niches.

Multistrain Infections with Lyme Borreliosis Pathogens in the Tick Vector

ABSTRACT Mixed or multiple-strain infections are common in vector-borne diseases and have important implications for the epidemiology of these pathogens. Previous studies have mainly focused on interactions between pathogen strains in the vertebrate host, but little is known about what happens in the arthropod vector. Borrelia afzelii and Borrelia garinii are two species of spirochete bacteria that cause Lyme borreliosis in Europe and that share a tick vector, Ixodes ricinus. Each of these two tick-borne pathogens consists of multiple strains that are often differentiated using the highly polymorphic ospC gene. For each Borrelia species, we studied the frequencies and abundances of the ospC strains in a wild population of I. ricinus ticks that had been sampled from the same field site over a period of 3 years. We used quantitative PCR (qPCR) and 454 sequencing to estimate the spirochete load and the strain diversity within each tick. For B. afzelii, there was a negative relationship between the two most common ospC strains, suggesting the presence of competitive interactions in the vertebrate host and possibly the tick vector. The flat relationship between total spirochete abundance and strain richness in the nymphal tick indicates that the mean abundance per strain decreases as the number of strains in the tick increases. Strains with the highest spirochete load in the nymphal tick were the most common strains in the tick population. The spirochete abundance in the nymphal tick appears to be an important life history trait that explains why some strains are more common than others in nature. IMPORTANCE Lyme borreliosis is the most common vector-borne disease in the Northern Hemisphere and is caused by spirochete bacteria that belong to the Borrelia burgdorferi sensu lato species complex. These tick-borne pathogens are transmitted among vertebrate hosts by hard ticks of the genus Ixodes. Each Borrelia species can be further subdivided into genetically distinct strains. Multiple-strain infections are common in both the vertebrate host and the tick vector and can result in competitive interactions. To date, few studies on multiple-strain vector-borne pathogens have investigated patterns of cooccurrence and abundance in the arthropod vector. We demonstrate that the abundance of a given strain in the tick vector is negatively affected by the presence of coinfecting strains. In addition, our study suggests that the spirochete abundance in the tick is an important life history trait that can explain why some strains are more common in nature than others.

Prolonged dormancy in the geophyte Allium amplectens on Vancouver Island

Prolonged dormancy occurs when a plant fails to appear above ground during the growing season. Although it may be an important life history trait of many geophytes, studies focusing on prolonged dormancy are infrequent and are concentrated on the Orchidaceae even though the phenomenon occurs in many taxonomic groups. We tracked individual plants of Allium amplectens (Amaryllidaceae) in permanent plots on Vancouver Island, which allowed us to determine rates of prolonged dormancy during a 4-year period. Dormancy rates per year averaged 38% and differed substantially among years. Over 70% of plants had a dormant period during the study. Dormancy periods of 2 years were almost as frequent as 1-year periods, and 8% of plants were dormant for 3 years. Plant density, which included small plants that we could not track in the plots, varied much more among years than did dormancy of tracked plants, suggesting that small plants may be especially prone to dormancy. High rates of prolonged dormancy and frequent multiyear dormancy indicate that this is an important life history feature of A. amplectens. We suggest that prolonged dormancy contributes to the ability of this species, and probably other species, to persist in dry habitats with fluctuating resources.

The effect of a supplementation program on the genetic and life history characteristics of an Oncorhynchus mykiss population

Conservation hatcheries, which supplement natural populations by removing adults or embryos from the natural environment and rearing and releasing parr, smolts, or adults back into their natal or ancestral streams, are increasingly being used to avoid extinction of localized populations of Pacific salmonids. We collected data before and during a steelhead ( Oncorhynchus mykiss ) supplementation program to investigate the effect that the program has had on the population’s genetic diversity and effective population size and any changes to an important life history trait (residency or anadromy). We found that supplementation did not cause substantial changes in the genetic diversity or effective size of the population, most likely because a large proportion of all of the steelhead redds in the river each year were sampled to create the supplementation broodstock. Our data also showed that the captively reared fish released as adults successfully produced parr. Furthermore, we found that during supplementation, there was an increase in the proportion of O. mykiss with anadromous ancestry vs. resident ancestry.

Spatial genetic analysis and long-term mark–recapture data demonstrate male-biased dispersal in a snake

Dispersal is an important life-history trait, but it is notoriously difficult to study. The most powerful approach is to attack the problem with multiple independent sources of data. We integrated information from a 14-year demographic study with molecular data from five polymorphic microsatellite loci to test the prediction of male-biased dispersal in a common elapid species from eastern Australia, the small-eyed snake Rhinoplocephalus nigrescens . These snakes have a polygynous mating system in which males fight for access to females. Our demographic data demonstrate that males move farther than females (about twice as far on average, and about three times for maximum distances). This sex bias in adult dispersal was evident also in the genetic data, which showed a strong and significant genetic signature of male-biased dispersal. Together, the genetic and demographic data suggest that gene flow is largely mediated by males in this species.