Egg Development Period Research Articles

Influence of Tempetature on Viability and Deveplopment of Heterakis gallinarum (Nematoda, Heterakidae) Eggs

Pinworms of the genus Heterakis Dujardin, 1845 parasitize a wide range of hosts, including a number of species of domestic and wild birds. These nematodes are ecologically adapted to the climatic conditions of many geographical zones, which contributes to their widespread distribution. The aim of the work was to investigate the influence of different temperature regimes at laboratory conditions on the growth, development and viability of eggs isolated from the gonads of female nematodes Heterakis gallinarum Schrank, 1788. The conducted studies established that, depending on the cultivation temperature, nematode eggs developed from 6 to 56 days, and their survival rate was from 67.7 to 83.7 %. The temperature of 25 °С was the most favourable for the development of H. gallinarum eggs, the development lasted 12 days and the highest number of eggs with motile infective larvae was formed (83.7 %). It was found that the period of egg development in cultures gradually decreased with increasing temperature: it was 56 days at 15 °C, 18 days at 20 °C, 12 days at 25 °C and 6 days at 30 °C. The survival rate of H. gallinarum eggs gradually increased with increasing temperature in regimes of 15 °С, 20 °С and 25 °С to 67.7 %, 80.7 % and 83.7 %, respectively. At a temperature of 30 °C, egg survival decreased slightly to 78.7 %. It was found that the development of H. gallinarum eggs from the zygote stage to the formation of motile infective larvae, depending on the temperature regime of cultivation, is accompanied by a decrease in egg length by 4.9–5.4 %, an increase in egg width by 4.1–7.6 % and a thinning of the shell by 9.5–28.6 %. Under different temperature regimes, the morphometric parameters of eggs during their development differ in terms of their length, width and shell thickness.

Hypothesised life cycle adaptation of stonefly (Plecoptera) in response to increased water temperatures

Water temperature is the most important and critical factor for freshwater invertebrates and it fluctuates with an increase in air temperature. In this study, the effect of water temperature on egg development was clarified in Stavsolus japonicus, and the response to climate change in stoneflies with long egg periods were considered. Water temperatures prior to 43 days before hatching likely do not affect egg development in Stavsolus japonicus. Instead, they use egg diapause as an adaptive strategy to survive hot summer conditions. Increased water temperatures may cause migration to higher elevations for stoneflies that have lower adaptability in their egg development period, with populations eventually becoming stranded where no higher elevation or cooler habitat is available. Species extinction is expected to increase with increasing temperatures, leading to reduced biodiversity in many ecosystems. Indirect effects of water warming on maturation and reproduction may lead to substantial reductions in benthic invertebrate populations.

Notes on Breeding of <i>Mertensiella caucasica</i> (Waga, 1876) (Urodela: Salamandridae) from Black Sea Coast of Turkey

The eggs and embryos of the Caucasian salamander were investigated in a breeding population (Kayabaşı, Trabzon). We found 24 eggs at the beginning of June 2018. About three weeks later, the shaped embryos were observed in the eggs. Finally, we performed the last visit to the study site one month later from the second visit. The hatching process was almost finished except for 1 egg that had an embryo inside and 2 – 3 eggs, no living embryos inside. We observed that the egg development period lasted about 50 days in the Kayabaşı population. The hatching period of the Caucasian salamander may differ according to different ecological conditions.

Use of a flow deflector to protect rheophilic fish spawning grounds during hydropeaking

AbstractRheophilic fishes are one of the ecological groups of fishes declining most quickly in number due to various habitat modifications and discharge regulations. Artificial rapid increases and decreases in discharge (hydropeaking) can cause severe damage to the eggs of rheophilic fishes. We investigated whether the effects of a water increase in hydropeaking on a spawning ground may be mitigated by a deflector installed at the top of the weir that diverts flow to other sections. At the research site, rheophilic asp (Leuciscus aspius) spawn annually in early spring, and their success might be affected by hydropeaking, with base discharge ranging from 3 to 7 m3 × s−1 and peak discharge ranging from 16 to 25 m3 × s−1 occurring 4 to 7 times during the asp spawning season and egg development period. To protect the adhesive eggs from detachment during peak discharge, a flow deflector (a wooden wall at the selected part of the weir) was installed to regulate discharge on the protected spawning ground. This measure allowed normal discharge under base flow conditions. During peak flow, a significant portion of the additional water was directed to the part of the river channel where egg abundance was lower and to the mill channel, where asp spawning was not present. While the total discharge increased 4.1 times compared to the base flow, the water discharge in the protected spawning ground increased only 2.7 times. This resulted in more than half of the asp eggs being retained in the protected channel. Although the use of such a measure is limited to specific local conditions where eggs are located just downstream of the weir, it can be a valid solution in highly fragmented rivers with hydropeaking and can lead to higher recruitment of rheophilic fishes.

Viability of exogenous stages of development of the causative agent of trichu-riasis of dogs under the influence of temperature

Urbanization processes to one degree or another occur in all regions of the planet. Large, small cities and megacities are created, leading to an urban ecosystem with unique abiotic and biotic factors. All this significantly affects the fauna, stability and viability of parasites of domestic dogs, which are representatives of the urban environment. The work aimed to establish the degree of viability of exogenous stages of development of Trichuris vulpis, parasitizing dogs, under the influence of different temperatures. It was established that in laboratory conditions, depending on temperature fluctuations (23 °C–29 °C), the development period of trichurises eggs to the invasive stage ranged from 15 to 27 days. At a 23 °C for 27 days, 74.0 % of invasive T. vulpis eggs were formed. At this temperature, 26.0 % of eggs died during their embryogenesis. At a temperature of 25 °C, the process of egg development to the invasive stage lasted 24 days, where 77.7 % of viable eggs were formed. At this temperature, 22.3 % of trichurises eggs died. As the temperature rises, the egg development period gradually shortens and is 18 days at a temperature of 27 °C, and 15 days at a temperature of 29°C. At the same time, the number of formation of viable invasive eggs decreased and amounted to 81.0 and 64.3 %, respectively, and the percentage of egg death increased to 19.0 and 35.7 %. The terms of formation of various stages of egg development in embryogenesis depended on the temperature, where as its indicators increased, the terms of these stages also shortened. The term of the zygote stage was shortened from 9 to 6 days, the stage of blastomere splitting – from 12 to 6 days, the leguminous embryo stage – from 15 to 6 days, the tadpole embryo stage – from 21 to 9 days, the larval stage – from 24 to 12 days, formation of a mobile larva – from 27 to 15 days. The conducted experimental studies expand the already existing data on the stability of the eggs of trichurises, which parasitize dogs, concerning the influence of temperature in the environment, and also make it possible to correctly establish the terms of preventive measures and prevent the infection of animals through environmental objects.

Riders on the storm? A short note on the biology of Severinia turcomaniae (Saussure, 1872) (Mantodea: Toxoderidae)

Summary New data are presented on the nymphal biology of a praying mantis, Severinia turcomaniae (Saussure, 1872), which has recently spread to the deserts of the Lower Volga Region. Nymphs of 3rd and 4th instars can be encountered in masses in August, suggesting a very short egg development period. They display a clear habitat preference for the tumbleweeds of Ceratocarpus arenarius L. It is hypothesized that the latter may serve for S. turcomaniae nymphs as a unique and efficient means for long-range dispersal and colonization of new localities, which would explain the fast colonization of the territories west of the Volga by S. turcomaniae, but not by Rivetina nana Mistshenko, 1967, another recent invader.

Effects of seasonal variation on the biology and morphology of the dusky cotton bug, Oxcarenus laetus (Kirby).

The dusky cotton bug (Oxycarenus laetus, KIRBY) a pest of several crops. The effects of winter and summer on the biology and morphology was investigated. The sampled eggs of dusky cotton bug (DCB) were kept under controlled environment for biological and morphological investigations. In winter, the mating duration of DCB was observed longer significantly (74.2 days), egg development period (3.93 days), an egg laying period (3.6 days) and hatching period (6.66 days) noted longer in winter season. Interestingly, average number of hatched egg (16.8 days) observed significantly higher in summer and the percentage of the hatching of eggs (81.95%) were also observed higher in summer as compare to winter. Whereas, the longevity of all nymph stages in winter longer days as compare to summer nymph stages. Moreover, differences were also observed between male and female development days between winter and summer. In the winter, female DCB development was suggestively higher as compare to summer (24 days). Whereas, the developmental days were noted considerably more in winter for males as compare to summer (14.93 days). On other hand, for morphological parameters, no differences were observed between winter and summer population of DCB.

Pre-laying movements of Yelkouan Shearwaters (Puffinus yelkouan) in the Central Mediterranean

The pre-laying exodus (PLE) is considered a crucial period in the breeding biology of Procellariiformes as it determines the success of egg production within a season and, therefore, a population’s reproductive output. However, it has scarcely been studied compared to other stages of the annual cycle. Here we present the first pre-laying tracks of the vulnerable Yelkouan Shearwater (Puffinus yelkouan) through the Global Positioning System tracking of birds breeding on the Maltese islands in the Central Mediterranean, and compare PLE core utilisation areas to known areas used during the chick-rearing period. Females spend, on average, 13 days foraging during egg development, reaching an average maximum distance of 325.5 km from their breeding colony to forage at offshore areas mainly south of the Maltese islands; these journeys are of longer duration and cover a greater distance than those undertaken by males, and by females that are not developing an egg, during the same period. There is little to no overlap between the PLE core utilisation areas and those used during chick-rearing by the same populations. This confirms our expectations that the PLE differs from foraging trips undertaken outside of the egg development period. Our results highlight the need for more research into the factors attracting egg-producing females to the PLE foraging areas and the importance of trans-boundary marine protection for the conservation of vulnerable seabirds.

Duration of life-cycle toxicity tests with the ostracod Heterocypris incongruens.

An acute sediment toxicity test using the ostracod Heterocypris incongruens is user friendly and has high sensitivity; however, a life-cycle test using this species has not been developed. The most challenging problem when developing a life-cycle test is that the egg development time varies greatly and is sometimes too long (> 150 d) to monitor. It is desirable to shorten the duration of life-cycle toxicity tests including the observation period of egg development while preserving the ecological relevance of the net reproductive rate (R0 ), an endpoint in the life-cycle test. Therefore, in the present study, we suggest a practical test duration for R0 using population growth rate (λ) as a measure of ecological relevance. We collected a range of life history characteristics of the ostracod by combining data from the literature and experimental results, constructed population matrix models, and calculated λ for 20 life history patterns. The results showed that a longer test period (> 150 d) did not increase the correlation coefficients between R0 and λ. Rather, a shorter test duration resulted in R0 being highly correlated with λ. Our results suggest that a life-cycle toxicity test using the ostracod can provide an ecologically relevant toxicity endpoint, even if the test is abandoned after approximately 50 d and unhatched eggs remain. Environ Toxicol Chem 2017;36:3443-3449. © 2017 SETAC.

Características produtivas de Kinosternon scorpioides nas fases de acasalamento, postura e eclosão, criados em cativeiro na Amazônia

Objetivou-se estudar os índices das características produtivas de muçuãs (Kinosternon scorpioides) visando nortear manejos adequados para a sustentabilidade da atividade. Analisou-se 84 acasalamentos, 742 posturas e 1979 nascimentos em cativeiro, determinando-se: a estação reprodutiva e a distribuição dos acasalamentos; a duração do acasalamento; a razão sexual; a duração do período de desenvolvimento do ovo (PDO); a frequência de múltiplas posturas; duração do período de nidificação; a correlação entre tempo de nidificação e número de ovos; o número de ovos viáveis; a correlação entre número, peso, comprimento e largura dos ovos; a análise descritiva para as características biométricas e peso dos ovos; a duração do período de incubação; a estação de nascimentos; as análises descritivas de peso e medidas corporais para os filhotes e a correlação entre as variáveis. A estação reprodutiva é sazonal, concentrando os acasalamentos na época mais chuvosa do ano com duração média de 00:23:00 h, com razão sexual de 2,38 ± 1,67:1. O PDO foi de 122,98 ± 45,38 dias. A distribuição das posturas apresentou uma tendência de clímax entre junho e agosto. A duração da nidificação foi de 02:57:00 h. A viabilidade dos ovos foi de 20%. A correlação entre as características biométricas, peso e o número de ovos foi positiva. Os resultados biométricos do ovo foram de 34,5 mm de comprimento e 18 mm de largura, com peso de 7,90 g. O período de incubação foi de 129,31 ± 19,57 dias, com os nascimentos se concentrando entre os meses de setembro a dezembro. As correlações das características biométricas com o peso dos filhotes foram positivas.

EFFECT OF FOOD TYPES AND HABITATS ON THE VALUE OF FEMALE MATURITY INDEX (FMI) AND GONADO SOMATIC INDEX (GSI) IN THE EGG PRODUCTION OF MANGROVE CRABS, Scylla serrata

<p>Mangrove crabs (Scylla serrata) is one of fishery commodities with high economic value for its good taste and nutrients content. Currently, increasing demand for this Crustacean species caused declining its population and for this reason, cultures of brooding crabs have been attempted. This study was carried out to investigate the egg development of mangrove crabs, with the main focus to study the effects of food types and habitats on the value of female maturity index (FMI) and gonado-somatic index (GSI). To investigate the effects of habitats, experiments were carrried out in the two habitats namely tidal flow of pond area and mangrove area. The spawning crabs were reared in a bamboo cage with the size of 2x1,5x1m3 divided into three paralel partition for 9-12 crabs with body weight of 200-250 grams. The crabs in the three partition were fed with three different foods, namely fish for the first partition, squid for the second, and mussel for the third. The results showed that no significant effect of foods and habitats was observed on the value of FMI. However, squid and mangrove habitats affected the growth, such as: an increase the wide of fifth abdomen segment, the widest abdomen segment and body weight during egg development periods. On the other hand, no significant different value of GSI was found on different habitats, but the food types affected the value of GSI.</p><p><br /><strong>Keywords</strong> : mangrove crabs, FMI, GSI, egg production</p>

The Potential for Less Invasive Inference of Resource Use: Covariation in Stable Isotope Composition between Females and Their Eggs in Bluegill

AbstractStable isotope analysis is frequently used to examine resource use in wild populations, but it often involves invasive or lethal methods of collecting tissue samples. The development of less invasive or nonlethal sampling techniques will expand the possible uses of stable isotopes. We examined whether fish eggs meet three basic requirements for inferring female resource use from them: (1) the isotope composition of the eggs is correlated with that of other maternal tissues for which isotope composition is known to be related to diet; (2) the isotope composition remains constant over the egg development period; and (3) dietary inferences using eggs are similar to those for other maternal tissues. Using artificial crosses, we tested the relationship between eggs and two commonly sampled maternal tissues (white muscle and liver) in wild‐caught Bluegills Lepomis macrochirus. We found that egg isotope composition was strongly correlated with that of other maternal tissues, particularly liver, and remained constant from prefertilization to the day of hatch, with no change in 13C and an increase of only 0.3‰ in 15N. Furthermore, the results of SIAR (Stable Isotope Analysis in R) mixing models indicated a large degree of overlap in diet estimates between eggs and the other maternal tissues. Overall, eggs can be reliably used to infer the prebreeding foraging ecology of female Bluegills throughout the egg development period.Received July 10, 2014; accepted October 28, 2014

Survival of eggs of Atlantic salmon (Salmo salar) in a drawdown zone of a regulated river influenced by groundwater

Groundwater may create refuges for Atlantic salmon egg survival during low flows in regulated rivers and thus play an important role for survival during winter. To investigate the links between the survival of salmon embryos and hyporheic hydrological processes during permanent winter drawdown, a 100-m-long and 50-m-wide gravel area in a regulated river, the River Suldalslagen, was used for an experimental study. Surface and subsurface water levels were monitored with 2-min time resolution by means of water pressure sensors placed in pipes. Temperature, conductivity and dissolved oxygen were also measured. Eight cylindrical boxes, each with two compartments (at 10- and 30-cm depth, respectively) containing 50 Atlantic salmon eggs, were placed in the river bed substrate of both the drawdown zone and the permanently wetted area as a reference. They were regularly checked for survival during winter from January to May, coinciding with egg development period for this river. Survival rates in boxes in the dewatered river bed were between 8 and 78% during winter, compared to 80 to 99% in the reference wetted area. The main driver for egg survival in the dewatered area was groundwater with sufficient oxygen levels.

Sensitivity to permethrin in a Dermacentor reticulatus population from eastern Poland in laboratory study

BackgroundThe action of chemical compounds on the Palaearctic tick D. reticulatus (Fabricius) (Acari: Amblyomminae) has been poorly investigated so far. Therefore, the effects of application of permethrin on engorged D. reticulatus females have been assessed, and the survival rate for the different developmental stages of the tick species in its non-parasitic phase of the life cycle was determined upon application of the pyrethroid.MethodsEach engorged D. reticulatus female, egg batch, unfed larvae (50 specimens), or unfed nymphs (10 specimens) were sprayed with 20 μl of 0.015625%- 0.250% solutions of a Coopex WP preparation, which corresponded to 0.78125- 12.5 μg of permethrin, respectively. The effect of permethrin in the preoviposition and oviposition periods was assessed based on the length of the egg development period, number of females capable of laying eggs, number and weight of eggs laid by the females, and indicators of female reproductive rate. Delayed effects of the action of the various permethrin doses were determined by quantitative and qualitative analysis of the course of embryonic development and larval hatch. The effect of permethrin on survival of the different tick stages was assessed at a temperature of 25°C and 90% RH 48 hours after application of permethrin to one to three day-old D. reticulatus eggs, seven to ten-day-old unfed larvae and nymphs.ResultsThe investigations demonstrated that at the doses applied permethrin decreased the reproductive rate of females, but only at the dose of 6.25 μg/1 specimen was the mean number of laid eggs drastically reduced, which may result in a decrease in tick abundance already in the first generation. The embryonic development of the eggs laid by the females treated with 6.25 and 12.5 μg of permethrin/1 specimen was highly disturbed. Irrespective of the permethrin dose applied, all eggs died within 48 hours after application. 100% of unfed D. reticulatus larvae and nymphs died within 48 hours after application of permethrin doses of 6.25 μg/50 specimens and 12.5 μg/10 specimens, respectively.ConclusionsPermethrin can be recommended for D. reticulatus control, particularly in the case of tick resistance to other chemical substances.

Effect of non-toxic, filamentous cyanobacteria on egg abortion in Daphnia under various thermal conditions

The aim of this study was to examine whether the presence of non-toxic filamentous cyanobacteria can cause egg abortion in Daphnia. To test this hypothesis, we fed females of Daphnia pulicaria with the green alga Scenedesmus obliquus from birth until eggs were laid in the brood chamber. Gravid Daphnia females were then exposed to media containing either S. obliquus or filaments of a non-toxic strain of the cyanobacterium Cylindrospermopsis raciborskii. The females were then observed throughout the whole period of egg development and all events of egg abortion were recorded. Experiments were conducted at three temperatures: 16, 20, and 24°C. In the presence of cyanobacteria, the proportion of aborted eggs ranged from 2.6 to 12.9%, compared with 0–1.8% in the green algae treatment. The number of aborted eggs, but not the number of egg-aborting females, tended to increase at higher temperature. Our data indicate that interference by non-toxic cyanobacterial filaments may affect the reproductive success of Daphnia, not only through suppression of their fecundity, but also via an increase in the number of aborted eggs. Therefore, the reproductive rate of Daphnia based on the fecundity of females may be overestimated in situations where filamentous cyanobacteria are present.

전남지역에서 꽃매미 부화시기 예측과 친환경 방제방법

본 시험은 온도 발육모델을 이용하여 꽃매미 알의 부화시기를 예측하고 약충과 성충 방제에 효과적인 친환경 자재선발 및 끈끈이트랩 색상별 유인효과를 찾기 위하여 수행하였다. 꽃매미 알은 15, 20, <TEX>$25^{\circ}C$</TEX>(14L:10D)에서 각각 55.9, 26.8, 21.6일 만에 부화하였고 부화율은 각각 61.9, 57.8, 30.4%로 온도가 높을수록 부화소요기간은 짧고 부화율은 낮았다. 알의 온도와 발육속도와의 관계식은 Y=0.0028X-0.0228 (<TEX>$R^2$</TEX>=0.9561)이었으며, 발육영점온도는 <TEX>$8.14^{\circ}C$</TEX>, 유효적산온도는 355.4일도였다. 위의 관계식에 의하여 전남지역 꽃매미 알의 부화시기는 5월 22일로 예측되었다. 꽃매미 약충방제에 효과적인 친환경자재는 제충국추출물, 고삼추출물, 데리스추출물이었고, 성충은 제충국추출물, 고삼추출물이었다. 황토색, 파랑색, 노랑색 끈끈이트랩 중에서 황토색끈끈이트랩의 유인량은 2주 동안에 약충 535마리, 성충 87.7마리였다. 황토색 끈끈이트랩은 꽃매미 약충과 성충의 유인포살효과가 우수하였다. This study was conducted to predict the hatching time of eggs of Lycorma delicatula, to select an effective environmentally-friendly agriculture material (EFAM) and to evaluate the attraction effect of brown sticky traps for controling of Lycorma delicatula nymph and adults. Eggs hatched 55.9, 26.8, 21.6 days after incubation at 15, 20, <TEX>$25^{\circ}C$</TEX> with 14L:10D condition and the hatching rates of egg were 61.9, 57.8, 30.4%, respectively. At high temperature conditions, egg development periods were shorter and the hatching rate was lower. The relationship between temperature and developmental rate was expressed by the linear equation Y=0.0028X-0.0228, <TEX>$R^2$</TEX>=0.9561. The low temperature threshold of eggs was <TEX>$8.14^{\circ}C$</TEX> and the thermal constant required to reach larva was 355.4 DD. According to this relationship, the mean estimated hatching date was <TEX>$22^{nd}$</TEX> May. The effective EFAM was natural plant extract, sophora extract, derris extract to nymph and natural plant extract, pyrethrum extract, sophora extract to adult. Among three colors of sticky trap : brown, blue and yellow, the brown sticky trap was the most attractive to nymphs and adults of L. delicatula over a 2 weeks trial period. It suggested that the brown sticky trap could be a very useful and environment-friendly control method for nymphs and adults of L. delicatula.

Effect of extract and powder of leaves of Eucalyptus camaldulensis ( Dehnh) on some biological aspects of potato tuber moth Phthorimaea operculella ( Zeller ) in laboratory

The research was conducted by using the ethanolic extract and powder of Eucalyptus leeves to evaluate their effect on some biological aspects of potato tuber moth in the laboratory . Results showed the important role of Eucalyptus extracts on potato tuber moth , the ethanolic extract of Eucalypt leeves prolonged the period of egg development which increased to 7.33 days by using 10000 ppm while the egg hatching percentage was decreased to 71 % at the same dose of extract , Adult emergence was decreased to74.67% and females fecundity decreased to 57.33 egg. Pupae treated with 10 % powder resulted in prolonged development period which reached to 15.33 days . Potato tubers treted with extract decreased number of egg on tubers by females to10.33 egg at 10000 ppm . There was also a clear effect for the ethanolic extract in larvae growth , percentage of number of first instar larva decreased by 91.3 % , and third instar larva decreased by 61 % when using 10000 ppm of ethanolic extract . These results indicated the possibility of using the natural materials of plants which are safe, cheep and active for pest control .

Biology of Invasive Monk Parakeets in South Florida

Abstract Monk Parakeets (Myiopsitta monachus) have been in Florida for >40 yrs, having been imported by the thousands for the pet trade. This conspicuous, charismatic species is now widely established, but relatively little is known about its population biology outside South America. We examined 845 parakeets from 385 nests from nest removals and collections by utility company personnel in 2003/2004 and 2006/2007 to document body size and aspects of reproductive biology and primary molt. Body measurements confirm Monk Parakeets in south Florida belong to the monachus subspecies. Adult males averaged 1.5 to 3.5% larger than females, but the body mass of females exceeded that of males during March–May, the period of egg development. The breeding season in south Florida commences in late winter/early spring with fledglings first appearing in the second week of June. Nest contents (eggs plus nestlings) averaged 5.6 for multiple-entry nests compared to 4.9 for single-entry nests. Over 94% of the adults we exam...

Predicting the population dynamics of the house dust mite Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) in response to a constant hygrothermal environment using a model of the mite life cycle

A generalised model of the life cycle of a house dust mite, which can be tailored to any particular species of domestic mite, is presented. The model takes into account the effects of hygrothermal conditions on each life cycle phase. It is used in a computer simulation program, called POPMITE, which, by incorporating a population age structure, is able to predict population dynamics. The POPMITE simulation is adapted to the Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) (DP) mite using published data on the egg development period, total development period, adult longevity, mortality during egg development, mortality during juvenile development, and fecundity of individual DP mites held at a range of constant hygrothermal conditions. An example is given which illustrates how the model functions under constant hygrothermal conditions. A preliminary validation of POPMITE is made by a comparison of the POPMITE predictions with published measurements of population growth of DP mites held at a range constant hygrothermal conditions for 21 days. The POPMITE simulation is used to provide predictions of population growth or decline for a wide range of constant relative humidity and temperature combinations for 30 and 60 days. The adaptation of the model to correctly take account of fluctuating hygrothermal conditions is discussed.

Maternal transfer of humoral specific and non-specific immune parameters to sea bream ( Sparus aurata) larvae

Immunisation of sea bream ( Sparus aurata L.) broodstock with a novel vaccine mixture of Photobacterium damsela subsp. piscicida SK7 ( Phdp) was performed during the period of egg development and the changes in specific and non-specific humoral immune parameters were measured. Total immunoglobulin level, specific antibody titre, anti-protease activity and lysozyme activity were significantly higher in immunised parents compared to the control. After spawning significantly higher anti-protease activity, lysozyme activity and total immunoglobulin level were detected in the eggs from immunised parents. Specific antibody titres against Phdp were only detected in the eggs from the immunised parents. The larvae from immunised parents also expressed significantly higher levels of specific and non-specific humoral immune parameters compared to the controls. A small amount of total immunoglobulin was detected in larvae decreasing gradually until day 8 post-hatching and then an increase was measured in larvae from immunised parents, whereas no immunoglobulin was detected at days 4, 6 and 8 in larvae from non-immunised parents. The specific antibody titre against Phdp was detected only in larvae from immunised broodstock until day 14 post-hatching. The higher humoral immune parameters in eggs and larvae from immunised parents in comparison to eggs and larvae from non-immunised parents, suggest transfer of maternal specific and non-specific immune factors.