In the embryonic blast cells of leeches, segmental identity is conferred in a cell-intrinsic manner (i.e., with temporal rather than spatial signals), at or shortly after the birth of the cell. If these blast cells are destroyed in only one of the two germinal bandlets that form the ventral midline, this can result in segment-specific features that fall out of register on either side of the leech body

The effect of larval feeding on the life history traits of the mottled emigrant butterfly Catopsilia pyranthe (Linnaeus, 1758) (Lepidoptera: Pieridae) was assessed to link life history variations as a function of food availability. The 0-day-old larvae of C. pyranthe were reared with varying quantity of food (100, 200, 400, 800, 1600 and 3200 mg/day) against a control set with ad libitum food availability

The temporal pattern of juvenile release by two species of viviparous asterinid sea stars that incubate their young in the gonads was documented. Parvulastra parvivipara released juveniles (400–3000 µm diameter) in 1–5 cohorts. Parents produced large juveniles (>1000-µm) irrespective of adult size. Released juveniles were larger than the retained juveniles. Most Cryptasterina hystera offspring were

Current coastal protection measures become increasingly insufficient under circumstances of climate change and increasing anthropogenic pressures. Aggregations of the ecosystem engineer Lanice conchilega (Pallas, 1766) stabilize the sediment bed of sandy shorelines. Therefore, this polychaete is considered an interesting target species in the search for nature-inspired designs in coastal zone management

The pleopodal fecundity of Pontastacus leptodactylus from Hirfanlı Dam (Turkey) was investigated. Reproductive period, length at first maturity, as well as the number, weight and diameter of pleopodal eggs were determined. The study was conducted monthly at six different stations from June 2017 to May 2018. Berried females were observed between December and May. L50 length at first maturity of the

Studies of broadcast spawning in corals are fundamental to our understanding of early life history characteristics, reproductive biology, restoration etc. Spawning of corals for research is routinely conducted, but this is mostly restricted to sites adjacent to reefs and from broodstock collected from the wild just prior to gamete release. Only recently has it been possible to induce predictable broadcast

Whitmania pigra is used in traditional Chinese medicine for the treatment of cardiovascular diseases and other chronic diseases, but its reproductive behaviour has not been well studied. The purpose of this study was to investigate the reproduction efficiency and mating system of W. pigra. The study was conducted under laboratory conditions. A total of 28 gravid leeches weighing 22.3 ± 6.1 g were used

The effect of age on fertilization capacity and reproductive potential were examined in males from a laboratory population of Acartia tonsa over their life time providing new empirical data for a foundational estuarine species. The reproductive functions spermatophore production (SPR), number of fertilized females (NFF), percentage of males that effectively fertilized females (M), egg production rate

The insect growth regulators (IGRs) chlorfluazuron, flufenoxuron and pyriproxyfen were evaluated, using the leaf-dip technique, on the various developmental and reproductive aspects of Spodoptera littoralis in the parental generation (P), first filial generation (F1) and second filial generation (F2). Additionally, the effect of these IGRs on nutritional indices was also evaluated. The effect on development

ABSTRACT In the present study, videos were recorded to observe oviposition in living, mature worms of Tubifex tubifex. After the formation of a lemon shaped cocoon around the clitellum at segments 11 and 12, mature eggs that have been stored in the ovisac at segments 12–14 begin to move into segments 11–12 through the constricted posterior end of the cocoon. Within a second or so, ovisac eggs emerge

Eco-friendly alternatives to unsafe conventional pesticides against disease vectors are currently needed. Host vaccination using an insect gut antigen is a feasible approach. Thus, the present study aimed to examine the effect of ingestion of antibodies from hamsters, raised via immunization of hamsters with a partially purified midgut lectin of Aedes aegypti, in a blood meal of this disease vector

The life histories of two common boreal-Arctic bryozoans – Electra pilosa and Callopora craticula – living on kelps in the White Sea are described for the first time using colony mapping. Colony functional dynamics (sexual, feeding, budding and rejuvenation) was traced seasonally via recording zooidal states. During the ice-free season the population of the zygote spawner E. pilosa was represented

Self-fertilization (selfing) is thought to evolve as a way of guaranteeing reproduction when mate availability is low. Nevertheless, because it often leads to inbreeding depression (ID), many hermaphrodites postpone reproduction via selfing when mates are scarce to wait for potential outcrossing opportunities. Owing to varying demographic histories and mate availabilities causing differing optimal

The molecular mechanisms underlying sex differentiation and gonad development remain elusive in crustaceans. Here, we report the cloning and characterization of a Sry-related high-mobility group family B2 gene (SpSoxB2) from an economic crustacean species, the mud crab Scylla paramamosain. The SpSoxB2 encodes a putative HMG-box protein (317 amino acids) clustered with invertebrate Sox14 homologues

Rensch’s rule attempts to explain the evolutionary processes that have resulted in the current patterns of sexual size dimorphism of several taxa. This rule predicts that sexual size dimorphism increases according to the average body size, when males are larger, decreasing when females are the largest sex. In decapod crustaceans, the general pattern of sexual size dimorphism is males with hypertrophied

The first detailed description of early development of the recently described European geophilid Geophilus serbicus is presented. Based on specimens from a natural population from the Balkan Peninsula, new insight was gained into the reproductive and developmental biology of the group. Changes in the morphology of brooded specimens allow 15 early developmental stages obligatorily dependent on prolonged

Recent molecular analyses characterized the freshwater crab Trichodactylus fluviatilis as a species complex. Considering this new scenario, studies about the population features are fundamental to understanding the biology of species belongs to this complex. We investigated the population from southeastern Brazil identify as Trichodactylus cf. fluviatilis, testing the hypotheses that sex ratio differs

The Brooks-Dyar rule predicts a geometric progression in the growth increments of successive instars. Although these increments are readily calculated as ratios, analysis of the relationship between these ratios has been more problematic. In the early twentieth century, the use of logarithms was proposed as a method for calculating the equation of the line. This is as close to a standardized method

Rotifers that engage in cyclical parthenogenesis produce two types of eggs: subitaneous eggs that hatch as clonal females and meiotic eggs that hatch as haploid males, or if fertilized, as females after a period of diapause (resting eggs). The ultrastructure of resting eggshells is known for some motile species, but there are limited data on subitaneous eggshells, and no data on any eggshells of sessile

Invertebrate model systems, such as nematodes and fruit flies, have provided valuable information about the genetics and cellular biology involved in aging. However, limitations of these simple, genetically tractable organisms suggest the need for other model systems, some of them invertebrate, to facilitate further advances in the understanding of mechanisms of aging and longevity in mammals, including

What mechanisms underlie aging? One theory, the wear-and-tear model, attributes aging to progressive deterioration in the molecular and cellular machinery which eventually lead to death through the disruption of physiological homeostasis. The second suggests that life span is genetically programmed, and aging may be derived from intrinsic processes which enforce a non-random, terminal time interval

The decline of tissue regenerative potential with the loss of stem cell function is a hallmark of mammalian aging. We study Botryllus schlosseri, a colonial chordate which exhibits robust stem cell-mediated regeneration capacities throughout life. Larvae, derived by sexual reproduction and chordate development, metamorphose to clonal founders that undergo weekly formation of new individuals by budding

Curcumin feeding of Drosophila larvae or young adults inhibits TOR and other known longevity genes and induces an extended health span in a normal-lived Ra strain adult. Combining larval curcumin feeding with an adult dietary restriction (DR) diet does not yield an additive effect. The age-specific mortality rate is decreased and is comparable with that of genetically selected long-lived La animals

Over a century ago, the zoologist Emile Maupas first identified the nematode, Rhabditis elegans, in the soil in Algiers. Subsequent work and phylogenic studies renamed the species Caenorhabditis elegans or more commonly referred to as C. elegans; (Caeno meaning recent; rhabditis meaning rod; elegans meaning nice). However, it was not until 1963, when Sydney Brenner, already successful from his work

The gastrointestinal tract, due to its role as a digestive organ and as a barrier between the exterior and interior milieus, is critically impacted by dietary, environmental, and inflammatory conditions that influence health and lifespan. Work in flies is now uncovering the multifaceted molecular mechanisms that control homeostasis in this tissue, and establishing its central role in health and lifespan

Hydra represents a unique model system for the study of senescence, with the opportunity for the comparison of non-aging and induced senescence. Hydra maintains three stem cell lineages, used for continuous tissue morphogenesis and replacement. Recent work has elucidated the roles of the insulin/IGF-1 signaling target FoxO, of Myc proteins, and of PIWI proteins in Hydra stem cells. Under laboratory

Sea urchins exhibit a very different life history from humans and short-lived model animals and therefore provide the opportunity to gain new insight into the complex process of aging. Sea urchins grow indeterminately, regenerate damaged appendages, and reproduce throughout their lifespan. Some species show no increase in mortality rate at advanced ages. Nevertheless, different species of sea urchins

Cnidarian Hydra polyps escape senescence, most likely due to the robust activity of their three stem cell populations. These stem cells continuously self-renew in the body column and differentiate at the extremities following a tightly coordinated spatial pattern. Paul Brien showed in 1953 that in one particular species, Hydra oligactis, cold-dependent sexual differentiation leads to rapid aging and

Comparative biogerontology has much to contribute to the study of aging. A broad range of aging rates has evolved to meet environmental challenges, and understanding these adaptations can produce valuable insights into aging. The supra Phylum Lophotrochozoa is particularly understudied and has several groups that have intriguing patterns of aging. Members of the lophotrochozoan phylum Rotifera are

The use of the tunicate Ciona intestinalis as a model system to study the relationship between regeneration and aging is reviewed. Ciona has powerful regeneration capacities, which fade with age. Some additional benefits are-, a relatively short life span, the ability to study regeneration in vitro, the close phylogenetic relationship between tunicates and vertebrates, and the host of molecular tools