Life-history Traits of Stethorus Gilvifrons (Mulsant) (Coleoptera: Coccinellidae) on Phytophagous Mites Eutetranychus Orientalis Klein (Acari : Tetranychidae)

The research aims to know the life cycle, feeding and mating behavior of predatory beetle S. gilvifrons, and was conducted at entomology laboratory of Assessment Institute for agri-cultural technology Malang - East Java. The treatments involved feeding behavior and capacity of the various instars and imago of S. gilvifrons. The number of mites consumed within 24 hours by each stage of beetle was also recorded. The average voracity of five individual predators for each instar was determined. The result showed that average life cycle of S. gilvifrons feed on E. orientalis was 4.11 + 0.78; 8 + 1.10; 3.83 + 0.41, respectively for egg, larva and pupa. The predator caught the preys from the front side, then chewed and sucked the body contents of adult preys or consumed the whole egg. The feeding capacity was greater in egg-laying than that in non egg-laying females and males. The smallest size of the cage (1.5 cm diameter x 5 cm long) and clear weather were the most preferred situation for S. gilvifrons mating, which usually occurs on the upper leaf surface. The male positioned itself over the female body and extended its aedeagus to reach the female

A comparative analysis of sperm storage in six brachyuran superfamilies: mating behavior, ecological variation and phylogenetic patterns

While life history traits are shaped by allometric, phylogenetic, environmental and behavioral factors, few comparative studies of brachyuran life history patterns have considered sperm storage traits as important components of reproductive strategies. To understand the evolutionary forces selecting for sperm storage and their interactions with other life history traits, I (1) used controlled laboratory experiments and field mating observations to examine variation in male sperm transfer patterns, (2) sampled variation in female reproductive output and sperm storage for two species across a latitudinal gradient, (3) conducted a survey of life history traits across a broad range of brachyuran taxa, and (4) used phylogenetic analyses to identify patterns in the evolution of life history traits in brachyurans. From mating experiments and observations on five species, I found that males transfer more sperm with longer than shorter copulation durations and that variation in copulation duration was shaped by differences in the species' ecologies. Latitudinal surveys of two species with contrasting mating systems identified seasonal and geographical variation in female reproductive output. While the variation in most reproductive traits could best be explained at smaller spatial scales, a sperm storing species, Callinectes sapidus became sperm limited at low latitudes. From a comparative survey of male and female life history traits across 61 species of brachyurans, I found that allometry, phylogeny and mating strategies explained much of the variation in life history traits. Using rigorous phylogenetic techniques, male life history traits showed more plasticity across the phylogeny than female traits suggesting male traits may be influenced more by behavioral and environmental factors. After correcting for phylogenetic signals, species with larger male sperm stores had larger amounts of sperm stored by the female. In summary this dissertation illustrates the importance of partitioning variation in mating behavior, phylogeny, environmental factors and allometry when examining the evolution of life history traits in brachyurans

Evolution of pycnogonid life history traits

The Pycnogonida is a class of arthropods with interesting life histories. Pycnogonids prey on hydroids and some invade hydranths while larvae. Males brood the eggs and larvae hatch as protonymphons. Questions relating to the evolution of life history characteristics were addressed. Evolutionary relationships were poorly understood. It was necessary to determine the relationships within the Pycnogonida and compared to other arthropods. Twenty-four morphological characters were coded for twenty-three pycnogonid genera and one fossil ancestor, Palaeoisopus problematicus. A branch and bound analysis resulted in fifteen most parsimonious trees. The Nymphonidae were found to be basal. The Ammotheidae were paraphyletic and led to two clades. The first contained the Callipallenidae, and Phoxichilidiidae. The second contained the remaining pycnogonids. A phylogeny was also compiled using sequences of the D3 expansion segments of 28S rDNA. This resolved relationships of sampled families as follows (Ammotheidae + ((Nymphonidae + Colossendeidae) + (Endeididae + (Pycnogonidae + Phoxichilidiidae)))). The Ammotheidae was found to be paraphyletic and basal. The results from the D3 region yielded perplexing relationships when compared with morphology. Phoxichilidium tubulariae Lebour 1947 is a valid species. It appeared to be specialists on the hydroid Tubularia larynx. Annual population dynamics of P. tubulariae were seasonal. Density of adult animals was highest in mid to late summer with reproduction being greatest in July and August. The abundance of pycnogonids peaked as the hydroid population declined. Some populations were shown to have two generations. Adult migration may play a larger role in the distribution of this species than larval dispersal. Phoxichilidium tubulariae had an atypical protonymphon type developmental mode that reduced the typical number of molts, and developed rapidly in the gastrovascular cavities of the host. It decreased developmental time from 35--40 days to 15--20 days. This was adapted to exploit the seasonal abundance of Tubularia larynx. The male looped the egg mass over his oviger. The larvae hatched, infected the hydroid, and developed inside the gastrovascular cavity of T. larynx. The larvae developed for several molts and then hatched, destroying the hydranth. The ancestral pycnogonid stock were external parasites. The internalization of the larval stages appeared to have happened at least twice

Heritability and genetic constraints of life-history trait evolution in preindustrial humans.

An increasing number of studies have documented phenotypic selection on life-history traits in human populations, but less is known of the heritability and genetic constraints that mediate the response to selection on life-history traits in humans. We collected pedigree data for four generations of preindustrial (1745–1900) Finns who lived in premodern fertility and mortality conditions, and by using a restricted maximum-likelihood animal-model framework, we estimated the heritability of and genetic correlations between a suite of life-history traits and two alternative measures of fitness. First, we demonstrate high heritability of key life-history traits (fecundity, interbirth interval, age at last reproduction, and adult longevity) and measures of fitness (individual λ and lifetime reproductive success) for females but not for males. This sex difference may have arisen because most of the measured traits are under physiological control of the female, such that a male's fitness in monogamous societies may depend mainly on the reproductive quality of his spouse. We found strong positive genetic correlations between female age at first reproduction and longevity, and between interbirth intervals and longevity, suggesting reduced life spans in females who either started to breed relatively early or who then bred frequently. Our results suggest that key female life-history traits in this premodern human population had high heritability and may have responded to natural selection. However genetic constraints between longevity and reproductive life-history traits may have constrained the evolution of life history and facilitated the maintenance of additive genetic variance in key life-history traits.</p

Life history of Monocystis parasites and genetic diversity of their hosts, the invasive Amynthas earthworms

Monocystis is a parasites in the phylum Apicomplexa that infects nearly 100% of earthworms; however, the parasites have low survivorship, low production of transmissible gametocysts, and seemingly lack schizogony. The purpose of this study was to investigate the improbable lifecycle and life history traits of a Monocystis species of the invasive Asian earthworms, Amynthas agrestis and A. tokioensis in Vermont. Preliminary data suggested that Monocystis sp. vary in life history traits between three sites sampled; therefore, it was necessary to investigate the genetic diversity and the mating system of its host, as the mating system is responsible for genetic variation. Random Amplified Polymorphic DNA (RAPD) markers revealed genetic variation within and among sites of both Amynthas spp. which appear to employ a mixed-mating system of both sexual and asexual reproduction demonstrated by the presence of both clonal and unique genotypes. The life history and life cycle of Monocystis sp. in A. agrestis was described by using microscopy to measure phenology and parasite stages and numbers. Amynthas spp. at Audubon had a shorter season and the parasites produced gametocysts earlier than at the other two sites. The parasite success rate at Audubon, Hort Farm, and Centennial Woods were 113.8%, 73.6%, and 0%, repectively. Audubon worms had higher numbers of gametocyts but a lower mean number of sporocysts per gametocyst (127.0) than did hosts at Hort Farm (145.8). Monocystis sp. has different life history traits and schedules to compensate for the length of the season and the genetic variation of its host

Dispersal and life-history traits in a spider with rapid range expansion

Background Dispersal and reproduction are key life-history traits that jointly determine species' potential to expand their distribution, for instance in light of ongoing climate change. These life-history traits are known to be under selection by changing local environmental conditions, but they may also evolve by spatial sorting. While local natural selection and spatial sorting are mainly studied in model organisms, we do not know the degree to which these processes are relevant in the wild, despite their importance to a comprehensive understanding of species' resistance and tolerance to climate change. Methods The wasp spider Argiope bruennichi has undergone a natural range expansion - from the Mediterranean to Northern Europe during the recent decades. Using reciprocal common garden experiments in the laboratory, we studied differences in crucial traits between replicated core (Southern France) and edge (Baltic States) populations. We tested theoretical predictions of enhanced dispersal (ballooning behaviour) and reproductive performance (fecundity and winter survival) at the expansion front due to spatial sorting and local environmental conditions. Results Dispersal rates were not consistently higher at the northern expansion front, but were impacted by the overwintering climatic conditions experienced, such that dispersal was higher when spiderlings had experienced winter conditions as occur in their region. Hatching success and winter survival were lower at the range border. In agreement with theoretical predictions, spiders from the northern leading edge invested more in reproduction for their given body size. Conclusions We found no evidence for spatial sorting leading to higher dispersal in northern range edge populations of A. bruennichi. However, reproductive investment and overwintering survival between core and edge populations differed. These life-history traits that directly affect species' expansion rates seem to have diverged during the recent range expansion of A. bruennichi. We discuss the observed changes with respect to the species' natural history and the ecological drivers associated with range expansion to northern latitudes

The Evolution of Life History Traits and Their Thermal Plasticity in Daphnia

Few studies have explored the relative strength of ecogeographic versus lineage-specific effects on a global scale, particularly for poikilotherms, those organisms whose internal temperature varies with their environment. Here, we compile a global dataset of life history traits in Daphnia, at the species-and population-level, and use those data to parse the relative influences of lineage-specific effects and climate. We also compare the thermal response (plasticity) of life history traits and their dependence on climate, temperature, precipitation, and latitude. We found that the mode of evolution for life history traits varies but that the thermal response of life history traits most often follows a random walk model of evolution. We conclude that life history trait evolution in Daphnia is not strongly species-specific but is ecogeographically distinct, suggesting that life history evolution should be understood at the population level for Daphnia and possibly for other poikilotherms

Nutrient allocations and metabolism in two collembolans with contrasting reproduction and growth strategies

Physiological mechanisms such as allocation and release of nutrients are keys to understanding an animal\u27s adaptation to a particular habitat. This study investigated how two detrivores with contrasting life‐history traits allocated carbon (C) and nitrogen (N) to growth, reproduction and metabolism. As model organisms we used the collembolans, Proisotoma minuta (Tullberg 1871) and Protaphorura fimata (Gisin 1952). To estimate allocations of C and N in tissue, we changed the isotopic composition of the animal\u27s yeast diets when they became sexually mature and followed isotope turnover in tissue, growth and reproduction for 28 days. In addition, we measured the composition of C, N and phosphorus (P) to gain complementary information on the stoichiometry underlying life‐history traits and nutrient allocation. For P. minuta, the smallest and most fecund of the two species, the tissue turnover of C and N were 13% and 11% day−1, respectively. For P. fimata, the equivalent rates were 5% and 4% d−1, respectively. Protaphorura fimata had the lowest metabolic rate relative to total body mass but the highest metabolic rates relative to reproductive investment. Adult P. fimata retained approximately 17% of the nutrient reserves acquired while a juvenile and adult P. minuta about 11%. N and P contents of total tissue were significantly higher in P. minuta than in P. fimata, suggesting that tissue turnover was correlated with high protein‐N and RNA‐P. Our results suggest that the lower metabolism and nutritional requirements by P. fimata than P. minuta is an adaptation to the generally low availability and quality of food in its natural habitat. The methodological approach we implemented tracking mass balance, isotope turnover and elemental composition is promising for linking nutrient budgets and life‐history traits in small invertebrates such as Collembola

Using life-history traits to explain bird population responses to changing weather variability

Bird population dynamics are expected to change in response to increased weather variability, an expression of climate change. The extent to which species are sensitive to effects of weather on survival and reproduction depends on their life-history traits. We investigated how breeding bird species can be grouped, based on their life-history traits and according to weather-correlated population dynamics. We developed and applied the linear trait–environment method (LTE), which is a modified version of the fourth-corner method. Despite our focus on single traits, 2 strategies—combinations of several traits—stand out. As expected, breeding populations of waterfowl species are negatively impacted by severe winters directly preceding territory monitoring, probably because of increased adult mortality. Waterfowl species combine several traits: they often breed at ground or water level, feed on plant material, are precocial and are generally short-distance or partial migrants. Furthermore, we found a decline in population growth rates of insectivorous long-distance migrants due to mild winters and warm springs in the year before territory monitoring, which may be caused by reduced reproduction due to trophic mismatches. We identify species that are expected to show the most significant responses to changing weather variability, assuming that our conclusions are based on causal relationships and that the way species, weather variables and habitat interact will not alter. Species expected to respond positively can again be roughly categorized as waterfowl species, while insectivorous long-distance migrants are mostly expected to respond negatively. As species traits play an important role in constructing functional groups that are relevant to the provisioning of ecosystem services, our study enables the incorporation of ecosystem vulnerability to climate change into such functional approache