Hatching Time Of Eggs Research Articles

Reproduction of Cernuella virgata (Da Costa, 1778) (Gastropoda: Geomitridae) in its natural environment in Southeast Turkey

ABSTRACT This study aims to investigate the reproductive characteristics of Cernuella virgata (Da Costa, 1778) from Diyarbakır, Southeast Turkey. From October 2023 to February 2024, the reproductive activities of over 300 individuals were monitored in Yeniköy Cemetery in Diyarbakır. The snails were first observed mating on 18 October 2023, after the autumn rains, with the first egg laying observed on 3 November 2023. The last mating observation occurred on 8 January 2024. A total of 225 individuals were noticed mating during this period. The number of eggs per clutch ranged from 36 to 114, with an egg hatching time between 18 and 32 days. Eggs were deposited amidst damp mosses, beneath decomposing vegetation, or on the damp soil surface. The spawning period lasts 12–13 weeks. Egg weights varied from 0.60 to 1.20 mg, and egg diameters ranged from 1.10 to 1.42 mm. Hatchling snails had shells with 1.5–2 whorls (protoconch), weighing between 1.15 and 1.72 mg on. The height of the hatchling’s shells ranged from 0.75 to 0.94 mm, and the width ranged from 1.21 to 1.38 mm. This study offers a detailed insight into the reproductive biology of C. virgata and marks the first record of the species in the region.

Histological analysis of Macrobrachium rosenbergii (de Man) eggs incubated in different salinities

Macrobrachium rosenbergii is the freshwater shrimp species of greatest economic interest, and its reproduction has been studied for commercial purposes. This study aimed to evaluate the effect of different salinities (0, 6, and 12 mg L-1) on the embryogenesis of this species. The females were observed daily according to their reproductive behavior. Upon the first sign of spawning, when their eggs were attached to the abdomen, they were collected for egg collection and transferred to the incubators at the respectively tested salinities. The eggs were collected every five days for up to 23 days, separated according to their stage of development, histologically processed, and stained for visualization of structural changes during embryogenesis using an optical microscope. From the egg's histological images at different embryonic development stages, the egg hatching time was evaluated, the changes that occurred in the eggs during embryogenesis, the total area of the eggs, the vacuole area, and the ratio between the vacuole area and the total area of the eggs. Differences were observed in hatching time, egg size, and vacuole area and area ratio. The 6 g L-1 of salinity treatment was statistically different from the other in all parameters analyzed. Therefore, it was concluded that 6 g L-1 of salinity positively influenced embryogenesis, as it presented hatches from the 15th day of embryogenesis, demonstrating that there was a greater speed of migration of vitellogenin for the formation of the embryo, accelerating embryogenesis and hatching of M. rosenbergii.

Effects of temperature and resource level on interspecific interactions in two species of Odonata larvae.

Identifying how temperature and food resources affect interactions between species is important for understanding how climate change will shape community structure in the future. Here, we tested how temperature and resource density affect survival and growth in the larval stage of two coexisting odonates: the damselfly Lestes sponsa and the dragonfly Sympetrum vulgatum. We performed a laboratory experiment at two temperatures (21 and 24°C) with two resource densities. We estimated the timing of egg hatching of individual egg clutches and thereafter the larval growth rate-, survival- and size-mediated priority effects under interspecific conditions. Eggs of both species hatched slightly faster at 24°C, and S. vulgatum eggs started hatching approximately 1 day earlier than L. sponsa eggs. However, this earlier hatching did not result in a size-mediated priority effect, that is, a higher predation on the later hatching L. sponsa. Nevertheless, L. sponsa larvae were significantly larger than S. vulgatum at hatching. Growth rate and survival were significantly higher: (1) at 24°C compared with 21°C, (2) at high compared with low-resource density and (3) in L. sponsa compared with S. vulgatum. Several significant interaction effects between resource density and temperature and between temperature and species were found. At high temperature, L. sponsa had a higher growth rate than S. vulgatum, but no difference in growth rate between species was found at low temperature. Additionally, a high-resource density resulted in a higher growth rate in both species, but only under high temperature. There was a negative relationship between growth rate and survival in both species, suggesting that the higher growth rate of larvae was to some degree driven by intraguild predation and/or cannibalism. Our results imply that resource levels interact with temperature to affect interactions between the species.

Temperature has an overriding role compared to photoperiod in regulating the seasonal timing of winter moth egg hatching.

To accurately predict species' phenology under climate change, we need to gain a detailed mechanistic understanding of how different environmental cues interact to produce the seasonal timing response. In the winter moth (Operophtera brumata), seasonal timing of egg hatching is strongly affected by ambient temperature and has been under strong climate change-induced selection over the past 25years. However, it is unclear whether photoperiod received at the egg stage also influences timing of egg hatching. Here, we investigated the relative contribution of photoperiod and temperature in regulating winter moth egg development using two split-brood experiments. We experimentally shifted the photoperiod eggs received by 2-4weeks compared to the actual calendar date and measured the timing of egg hatching, both at a constant temperature and in combination with two naturally changing temperature treatments - mimicking a cold and a warm year. We found an eight-fold larger effect of temperature compared to photoperiod on egg development time. Moreover, the very small photoperiod effects we found were outweighed by both between- and within-clutch variation in egg development time. Thus, we conclude that photoperiod received at the egg stage does likely not play a substantial role in regulating the seasonal timing of egg hatching in the winter moth. These insights into the regulatory mechanism of seasonal timing could have important implications for predicting insect climate change adaptation, as we might expect different targets of selection depending on the relative contribution of different environmental cues.

Effect of Entomopathogenic Fungi to Eggs and Nymphs Survival of Halyomorpha halys (Hemiptera: Pentatomidae) Under Laboratory Conditions.

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is becoming a major pest of Greece's agricultural production, including tree fruit. Until now, the control of this pest has been based on conventional methods, with the application of chemical insecticides being the primary option. However, the wide distribution of H. halys, in combination with the large area of tree fruit production in Greece, raise the need for alternative control methods. In this study, we investigated the possibility of implementing microbial control agents for managing H. halys. Eggs and nymphs of H. halys were treated with 15 native entomopathogenic fungal isolates and their virulence was evaluated in the laboratory. After treatment, egg hatching time was recorded for 7days and ranged from 4.5 to 7.0days. Nymphal survival was recorded daily for 7days following application and ranged from 2.1 to 6.6days for second instar nymphs and 3.7 to 6.8days for fourth instar ones. Beauveria varroae isolate displayed the highest toxicity to all H. halys stages that were tested and could be considered a promising biocontrol agent of this insect. Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.οκ.

Lethal and Sublethal Effects of Cyromazine on the Biology of Musca domestica Based on the Age-Stage, Two-Sex Life Table Theory.

Cyromazine is a triazine insect growth regulator insecticide that is recommended for control of Musca domestica worldwide. Cyromazine is highly effective in causing mortality of M. domestica; however, some aspects of its lethal and sublethal effects on the biology of M. domestica are still unknown. The present study explored lethal and sublethal effects on several biological traits and population parameters of M. domestica. Concentration-response bioassays of cyromazine against third-instar larvae of M. domestica exhibited sublethal and lethal effects from concentrations of 0.03 (LC10), 0.06 (LC25), and 0.14 (LC50) μg/g of a larval medium. Exposure of M. domestica larvae to these concentrations resulted in reduced fecundity, survival, longevity and oviposition period, and delayed development of immature stages (i.e., egg hatch time and larval and pupal durations) in the upcoming generation of M. domestica. The values of population parameters such as intrinsic rate of increase, finite rate of increase, net reproductive rate, age-specific survival rate and fecundity, and age-stage life expectancy and reproductive value, analyzed using the age-stage and two-sex life table theory, were significantly reduced in a concentration-dependent manner in comparison with the control group. In conclusion, the study highlights the significant effects of cyromazine on the biology of M. domestica that could help suppress its population in cases of severe infestations.

From Field Data to Practical Knowledge: Investigating the Bioecology of the Oak Lace Bug-An Invasive Insect Species in Europe.

Corythucha arcuata, commonly known as the oak lace bug (OLB), is an insect species originally native to North America that has become an invasive species of significant concern in Europe. This invasive pest has been observed in various European countries, raising concerns about its impact on forest ecosystems. In 2015, it was first documented in Romania, further highlighting the need for research on its bioecology and life cycle. This study investigated the bioecology of the OLB in the southern region of Romania, focusing on its life cycle, development, and population dynamics. The results indicated that the OLB has three generations per year and overwinters in the adult stage in sheltered locations. Temperature significantly influenced the timing of egg hatching, nymph appearance, and adult development, with variation observed between generations. Additionally, a life table analysis provided insights into the population dynamics of the OLB in its natural environment, revealing variation in egg laying trends across generations. This research contributes to a better understanding of the OLB's bioecology and provides essential data for forest managers developing science-based management strategies to mitigate its impact. By elucidating the life cycle and development patterns of the OLB in southern Romania, this study aids in the development of predictive models and life tables tailored to the region. These findings empower forest managers with the knowledge needed to make informed decisions for effective OLB management, ultimately preserving the health of forest ecosystems.

Novel hatching cue in the neotropical damselfly Megaloprepus caerulatus: larval adaptation and maternal constraint

The evolution of sibling cannibalism as a maternal strategy is particularly challenging to explain when nurseries are shared among multiple females. Such is the case for the damselfly, Megaloprepus caerulatus, whose females lay eggs in bark above the water line in large, water-filled tree holes. Asynchronous egg hatching appears to be a maternal bet-hedging strategy to increase the chances that cannibalistic offspring hatch during windows of opportunity, which occur after the remaining large larvae emerge, having eaten all others. We investigated the proximate causes of asynchronous hatching. By monitoring the pattern of egg hatching under ambient temperature in an insectary, we found that egg hatching co-occurred with lower ambient temperatures, which decreased with increasing rainfall. Treating fully developed eggs to a lower temperature for two hours triggered increased hatching relative to controls at ambient temperature. Dissection of control clutches indicated that embryonic development of siblings was asynchronous. Results suggested that the hatching trigger is adaptive. Rainfall assures a recharge of the larval habitat with water and provides wet conditions essential for neonate mobility on bark. Only 40% of neonates in a 4-day drying treatment survived; none survived the 8- and 14-day treatments. This novel hatching trigger should increase the number of neonates entering the nursery after rains, constraining a mother’s control over the timing of egg hatch, while increasing the competition among related and unrelated offspring for limited windows of opportunity in the shared nursery.

Degree-day-based model to predict egg hatching of Philaenus spumarius (Hemiptera: Aphrophoridae), the main vector of Xylella fastidiosa in Europe.

Philaenus spumarius L., the main vector of Xylella fastidiosa (Wells) in Europe, is a univoltine species that overwinters in the egg stage, and its nymphs emerge in late winter or spring. Predicting the time of egg hatching is essential for determining the precise times for deploying control strategies against insect pests. Here, we monitored P. spumarius eggs from oviposition to egg hatching together with the daily temperatures and relative humidities at four field locations that were located at different altitudes in central Spain. The collected data were used to build a growing degree day (GDD) model to forecast egg hatching in the Iberian Peninsula. Furthermore, the model was validated with field observations that were conducted in Spain. The model was then used as a decision-support tool to calculate the optimum timing for applying control actions against P. spumarius. Our results suggest that controlling nymphs at two different dates would target the highest percentages of nymphal populations present in the field. Our model represents a first step for predicting the emergence of nymphs and adopting timely control actions against P. spumarius. These actions could limit disease spread in areas where X. fastidiosa is present.

Embryonic Development and Eclosion Season of New Species <i>Berastagia</i> (Lepidoptera: Pyralidae) from Taiwan

This paper describes a new species of the snout moth Berastagia tainanica sp. nov. (Lepidoptera: Pyralidae) from Taiwan. From 2009 to 2016, a biology study was conducted on population dynamics and embryonic development. Spring season is the peak of the eclosion of overwintering larvae or pupae. The average longevity of adult was 14.8 ± 6.2 days (N = 174), the average number of eggs laid was 259 ± 3 eggs/moth (N = 2), the hatching rate of eggs was 95.4% (N = 262), and the average hatching time of eggs was 99.6 ± 18.6 hours (N = 68). The average body length of males was 5.64 mm ± 0.91 mm (N = 30), and the average body length of females was 6.28 mm ± 0.84 mm (N = 30). This finding indicates that female snout moths are larger than males (Global R = 0.058, P = 0.012). The snout moth eclosion rate was 16.9 moths/100 pods in the first year (2010/2011, N = 2,224 pods) and 10.9 moths/100 pods in the second year (2014/2015, N = 6,382 pods). The pod borer rate was 31.8% (N = 707) and the seed borer rate was 41.2% (N = 3,628) in the first year, whereas the pod borer rate was 76.2% (N = 6,382) in the second year.

Environmental Manipulations to Increase Hatching Rate of Catfish Eggs (Pangasius sp.): A Review

Catfish is the primary commodity of freshwater consumption fish that is widely cultivated with a high protein content of 68.6% and a high selling price. In addition, catfish meat is believed to be capable of preventing heart and cardiovascular disease because its unsaturated fats. Catfish skin can be used as a source of collagen in the culinary, cosmetic, and health fields. Catfish spawn all year round because of the abundance of food. The environment can help stimulate the synthesis of reproductive hormones in the reproductive activity of catfish. Environmental manipulations such as temperature, pH and salinity have different effects on the hatchability of catfish (Pangasius sp.) eggs. High temperatures can speed up the hatching time of the eggs but drop the hatching percentage and survival rate because high temperature activates the chorionase enzyme containing pseudokeratin which softens fish egg shells. In contrast to the pH treatment, a pH that is too acidic will deactivate the work of the chorionase enzyme so that the shells of fish eggs are difficult to break, resulting in a low percentage of hatching and survival rate with the longest hatching time. Salinity works by balancing the osmoregulatory pressure in the shell with the environment. A high salinity concentration can damage the egg by breaking into and swelling the eggshell, causing a low survival rate. On the other hand, eggs not treated with salinity were reported to have the lowest hatching percentage due to fungi attacking the eggs causing embryos to die. Salinity does not affect egg hatching time.

PERKEMBANGAN EMBRIO DAN PERFORMA AWAL LARVA IKAN TAWES (Barbonymus gonionotus)

The research was carried out from November 2021 to January 2022, and the trial period from November 1 to November 12, 2021 at the Germplasm Research Installation for Freshwater Fisheries in Cijeruk, Bogor, West Java. This study aims to determine the embryonic development and early performance of Tawes fish (Barbonymus gonionotus) larvae. This experimental study used 2 male tawes broodstock, 2 female brood fish, and anesthetic drugs. Parameters observed included observation of embryos and early performance of Tawes larvae. The embryo data were analyzed in a qualitative descriptive manner with pictures of each phase of egg development and followed by data on egg hatching time. The results showed that the early embryonic development of Tawes fish generally includes the stages of egg division, morula, blastula, gastrula, segmentation and hatching. The initial performance of Tawes larvae reared at 28oC showed abnormality values ​​of Tawes fish of 5.78±1.52%, average egg diameter of 1.02±0.04 mm, average initial length of larvae of 7.28±0.55 mm.

Multiple Effects of Egg Weight, in Ovo Carbohydrates, and Sex of Birds on Posthatch Performance in Broilers.

Simple SummaryFuture technologies in poultry nutrition must support the growth, gut health, and energy status of the birds. One of these technologies is in ovo nutrition, in which nutrients enter the egg by a needle puncture without any harm to the embryo. Amino acids, vitamins, and even carbohydrates can be injected into various parts of the egg, mainly during the last days of hatch. Carbohydrates, as a primary energy source, are crucial for the avian body, especially on the day of hatch, when the carbohydrate resources of the egg yolk do not meet the needs of the embryo. In our study, a carbohydrate mixture composed of disaccharides and glucose was tested to examine the performance and carcass characteristics of broiler chickens. It can be concluded that a carbohydrate mixture tends to reduce hatchability; however, the correct quantity of fluids, injection day, and osmolality of the mixture still need to be specified. In addition, many other factors can determine performance, such as the hatching day, sex, and the size or weight of the egg. On the other hand, this technique may improve carcass traits. Further studies are needed to refine the method to avoid embryo death.Chickens raised for their meat (Gallus gallus domesticus) tend to have a critical phase of life right after hatching due to the management of modern production systems. Early nutrition strategies such as in ovo intervention can be an alternative means to support growth and gut health by compensating for the energy deficit after pipping out of the egg. In the current study, 1200 Ross 308 eggs were used to examine the effects of a complex carbohydrate solution of disaccharides and glucose applied in ovo on hatchability, the hatching time of different-sized eggs, and the development, performance, and carcass characteristics of broilers of both sexes. The eggs were divided into three treatment groups: intact (NT), in ovo saline (ioS), and in ovo carbohydrate mixture (ioCH). The incubation protocol was performed according to the recommendations of Aviagen (2019), and the in ovo process was carried out on day 17 by manually injecting 0.5 mL of the solutions into the amniotic fluid. After hatching, the birds were kept in floor pens until day 35 and fed ad libitum in a three-phase feeding program. Body weight, average daily weight gain, feed intake and conversion, and carcass characteristics were measured during the trial. In ovo carbohydrates reduced hatchability by 15%, while growth performance and the weight of thigh and breast muscle were enhanced significantly (p < 0.05) compared with ioS as a possible outcome of carbohydrate-to-muscle satellite cell proliferation and protein accumulation. However, further study is needed to refine the in ovo carbohydrate supplementation method to minimize the mortality of embryos during hatching.

Embryo Development and Effects of Temperature, Salinity, and Light Intensity on Egg Hatching of Calanoid Copepod Bestiolina amoyensis (Calanoida: Paracalanidae)

Bestiolina amoyensis distributes in subtropical inshore waters across the Pacific Ocean, with a relatively long reproductive lifespan and high intrinsic population increase rate compared with other small paracalanid species, which makes it a good candidate to develop culture techniques for hatchery larval rearing. However, the reproductive biology of this subtropical broadcast spawning species is still largely unknown. The present investigation provides the first published data on the embryo development and effects of different light intensities (0, 500, and 1,000 lx), temperatures (16°C, 18°C, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, and 34°C), and salinities (22, 24, 26, 28, 30, 32, and 34 psu) on hatching success rates of B. amoyensis. The same batch of eggs were collected from gravid females to observe their embryonic development and incubated under designed light intensities, temperatures, and salinities. Results showed that the whole embryonic development of B. amoyensis lasted, on average, 6 h and 40 min at 26°C, and egg hatching time of B. amoyensis shortened exponentially with the increasing temperature. The highest egg hatching rate (100%) was recorded from the 0-lx treatment, indicating that the dark condition was favorable for the egg incubation of B. amoyensis. The optimum temperature and salinity range for the hatching success of B. amoyensis was 22°C–30°C (above 94%) and 22–34 psu salinity (above 88%), respectively, indicating that B. amoyensis had wide adaptability to temperature and salinity. Light and too low or high temperature leads to abnormal embryonic development and malformed nauplii. The relatively wide adaptability to temperature and salinity and fast embryo development also suggests that B. amoyensis was a good candidate as live feed for hatchery larval rearing.

Determining the Effect of Different Reproduction Factors on the Yield and Hatching of Tenebrio Molitor Eggs.

Simple SummaryThis study investigated the effect of various factors on the reproduction of the yellow mealworm Tenebrio molitor. More specifically, the effect of (1) the use of a grid, (2) oviposition duration, (3) age of the beetles and (4) beetle density were examined. For these parameters, it was investigated how they influence the number of eggs laid per beetle as well as the egg hatching rate and time. All these factors had a clear impact on the number of eggs. The results of this study will help producers to optimize their breeding method in order to obtain higher yields.Whereas the production of conventional livestock can rely on years of knowledge and experience, the mealworm production industry is still in its early stages. Although the yellow mealworm Tenebrio molitor has been cultivated as feed for pets and zoo animals for quite some time, the optimization of the reproduction process has not been widely explored. For reproduction, beetles are placed in crates supplemented with a substrate to oviposit their eggs. After a specified time, the beetles are removed, and the eggs are further cultivated to develop into larvae. Factors such as oviposition duration and beetle density influence the number of produced mealworms per beetle, partly due to the cannibalistic behavior of the beetles. However, reproductive success has mostly been assessed by determining the number of offspring several weeks after oviposition. As a result, the number of eggs laid and their hatch rates are unknown. In this research, eggs are separated from the oviposition substrate, i.e., harvested. This approach allows to determine the influence of beetle density, oviposition duration, beetle age and the use of a grid during oviposition on the number of eggs produced and the egg hatching rate and timing thereof. In addition, the influence of the harvesting method on the hatching of T. molitor′s eggs was determined.

PERKEMBANGAN EMBRIO DAN PERFORMA AWAL LARVA IKAN TENGADAK (Barbonymus schwanennfeldii)

This experiment was conducted from May 2021 – September 2021 at the Freshwater Fishery Germplasm Research Installation in Cijeruk, Bogor, West Java. This study aimed to determine the stages of embryonic development and early larval performance that occurred in Tengadak fish (Barbonymus schwanenfeldii). This experimental study used two female fish, two male fish, and anaesthetic drugs. Parameters observed included observation of embryos and early performance of squirrelfish larvae. The embryo data were analyzed in a qualitative descriptive manner with pictures of each egg development phase and then data on egg hatching time. The results showed that the early development of the embryo in trout generally includes cleavage stages, morula, blastula (blastoderm formation), gastrula (closure of the yolk sac), segmentation and hatching. The initial performance of the scorpion fish larvae reared at a temperature of 28oC showed an abnormality value of 5.7±2.5%. The average diameter of the egg yolks of the tee-fish was 39.42±4.41 µm, and the average initial length of the trout larvae was 18.46±1.32 µm.

Effects of Soil Temperature and Moisture on the Development and Survival of Grasshopper Eggs in Inner Mongolian Grasslands

Grasshopper eggs overwinter in soil for almost half a year. Changes in soil temperature and moisture have a substantial effect on grasshopper eggs, especially temperature and moisture extremes. However, the combinatorial effect of temperature and moisture on the development and survival of grasshopper eggs has not been well studied. Here, we examined the effects of different soil moistures (2, 5, 8, 11, 14% water content) at 26°C and combinations of extreme soil moisture and soil temperature on the egg development and survival of three dominant species of grasshopper (Dasyhippus barbipes, Oedaleus asiaticus, and Chorthippus fallax) in Inner Mongolian grasslands. Our data indicated that the egg water content of the three grasshopper species was positively correlated with soil moisture but negatively correlated with hatching time. The relationship between hatching rate and soil moisture was unimodal. Averaged across 2 and 11% soil moisture, a soil temperature of 35oCsignificantly advanced the egg hatching time of D. barbipes, O. asiaticus, and C. fallax by 5.63, 4.75, and 2.63 days and reduced the egg hatching rate of D. barbipes by 18%. Averaged across 26 and 35°C, 2% soil moisture significantly delayed the egg hatching time of D. barbipes, O. asiaticus, and C. fallax by 0.69, 11.01, and 0.31 days, respectively, and decreased the egg hatching rate of D. barbipes by 10%. The hatching time was prolonged as drought exposure duration increased, and the egg hatching rate was negatively correlated with drought exposure duration, except for O. asiaticus. Overall, the combination of high soil temperature and low soil moisture had a significantly negative effect on egg development, survival, and egg hatching. Generally, the response of grasshopper eggs to soil temperature and moisture provides important information on the population dynamics of grasshoppers and their ability to respond to future climate change.

Timing of increased temperature sensitivity coincides with nervous system development in winter moth embryos.

ABSTRACTClimate change is rapidly altering the environment and many species will need to genetically adapt their seasonal timing to keep up with these changes. Insect development rate is largely influenced by temperature, but we know little about the mechanisms underlying the temperature sensitivity of development. Here, we investigate seasonal timing of egg hatching in the winter moth, one of the few species which has been found to genetically adapt to climate change, likely through selection on temperature sensitivity of egg development rate. To study when during development winter moth embryos are most sensitive to changes in ambient temperature, we gave eggs an increase or decrease in temperature at different moments during their development. We measured their developmental progression and time of egg hatching, and used fluorescence microscopy to construct a timeline of embryonic development for the winter moth. We found that egg development rate responded more strongly to temperature once embryos were in the fully extended germband stage. This is the phylotypic stage at which all insect embryos have developed a rudimentary nervous system. Furthermore, at this stage, timing of ecdysone signaling determines developmental progression, which could act as an environment dependent gateway. Intriguingly, this may suggest that, from the phylotypic stage onward, insect embryos can start to integrate internal and environmental stimuli to actively regulate important developmental processes. As we found evidence that there is genetic variation for temperature sensitivity of egg development rate in our study population, such regulation could be a target of selection imposed by climate change.

Trophic transfer and toxicity of heavy metals from dengue mosquito Aedes aegypti to predator dragonfly Tramea cophysa.

Heavy metal pollution in aquatic habitats can be detrimental to both prey and predators in a food web. To investigate the potential for bio-transfer and bioaccumulation of heavy metals between specific trophic levels, 3rd instar larvae of Aedes aegypti were exposed to mercury (Hg), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) for three consecutive generations and fed to dragonfly (Tramea cophysa) nymphs. Exposure to Hg caused the highest mortality in A. aegypti larvae and T. cophysa nymphs. Bioaccumulation and life-history parameters of A. aegypti, including egg hatching time, larval and pupal duration, male and female life span, and fecundity, were also evaluated after metals exposure. All life-history parameters except larval duration were significantly affected by heavy metal treatments. Bioaccumulation of metals in A. aegypti larvae and adults gradually and significantly increased from 1st to 3rd generation. To the best of our knowledge, this is the first study describing the acute toxicity of heavy metals to mosquitoes. Our study shows that heavy metals cause dietary toxicity to an aquatic predator, dragonfly, via trophic transfer, which could have considerable consequences on aquatic ecosystems.

Biology of citrus butterfly Papilio demoleus L. (Papilionidae: Lepidoptera)

The present research was carried out to study the biology of the citrus butterfly Papilio demoleus L. (Papilionidae: Lepidoptera) under laboratory conditions. Observations on lifespan (days), adult longevity on various diets and leaf area consumed by various larval instars per day (sq. cm). Also, descriptions and measurements of various stages of P. demoleus on Citrus limon (L.) were carried out in vitro at room temperature. Results showed that, mean egg-hatching time was about 3.25±0.91 days and 5.5±1.28, 4.5±0.57, 3.75±0.48, 3.75±0.48, 3.25±0.70 days for 1st, 2nd, 3rd, 4th and 5th instars respectively. Pupal stage and average adult longevity recorded 6±0.57 and 3±0.57 days respectively. Adult longevity on distilled water, 10% honey, pure honey and 50% sugar + water solution recorded 2, 3, 5 and 3 days respectively. The mean value for egg size is 1±0 mm and 2.4±0.85, 16.75±1.25, 21.5±1.73, 32.0±0.81, 35.7±1.09 mm for 1st, 2nd, 3rd, 4th and 5th instar respectively. The size of pupa and adult were 26±1.28 and 98.7±2.89 mm respectively. The mean values for leaf area consumed per day were 2±0.34, 8.87±2.37, 15±1.41, 62±4.24, and 108±3 cm2 for 1st, 2nd, 3rd, 4th and 5th instar respectively. The results on life span, adult longevity with various food sources and leaf area consumption provide valuable scientific evidence on building citrus butterfly management practices and helps to access damage.