Environmental control of the seasonal life cycle of a zoophytophagous mirid, <Emphasis Type="Italic">Adelphocoris triannulatus</Emphasis> (Hemiptera: Miridae)

Adelphocoris triannulatus (Stål) (Heteroptera: Miridae) is a zoophytophagous bug that inhabits grasslands and crop fields, and is widely distributed in eastern Asia. In this study, the seasonal occurrence and environmental factors controlling the seasonal life cycle of this bug were investigated in a local population in southern Kyushu, Japan. When insects were reared under different photoperiods at 20 and 25 °C, they produced diapause or nondiapause eggs depending on the photoperiod: when reared under short-day photoperiods (≤?13 h/day), females laid diapause eggs, whereas they laid nondiapause eggs when reared under long-day photoperiods (≥?14 h/day). Because the developmental duration of the pre-adult stages and maturation (minimum duration of one generation) is estimated to be approximately 30 days at summer temperatures, these results suggest that this bug has a multivoltine seasonal life cycle. In agreement with the laboratory results, only nondiapause eggs were produced until mid-August in the field, and an increasing proportion of diapause eggs were produced from early September. In addition to these findings, field sampling from spring to autumn in 2009 indicated that three or four generations were produced in one year. These results suggest that egg diapause plays a role in preventing nymphs of A. triannulatus from developing in winter, and thereby ensures the survival of the population in adverse seasons.     

Variation the oviposition behavior by the stingless bee,Heterotrigona itama (Hymenoptera,Apidae, Meliponini)

A study to determine the variation of ovipositioning behavior of stingless bees, Heterotrigona itama (Cockerell, 1918) was conducted on three colonies on June 2015. A digital single-lens reflex (DSLR) camera with a macro lens attached was used to record every movement of H. itama in its colonies for 20 min hour between 0800 h and 2000 h for seven days and seven month. The daily egg laying rate and time for laying eggs in colony-B and colony-C were significantly (P ? 0.05) higher than the colony-A. However, time to close the brood was not significantly different among colonies. The fastest egg oviposition time was 4 s by the colony-B and the slowest was 6 s by the colony-A. In addition there are no significant trends on brood produced per day, laying time of eggs, and the closing time of the brood after the oviposition process from June to December 2016. This result is useful for understanding the behavior of egg laying process by the queen bees and necessary to deal with problems of management and reproduction in the near future.     

Reproductive plasticity in <Emphasis Type="Italic">Petrolisthes armatus</Emphasis> (Anomura,Porcellanidae): a comparison between a Pacific and an Atlantic population

The porcellanid crab Petrolisthes armatus, with a known geographic distribution covering a wide range of latitudes, was selected to conduct a comparative study on egg production and reproductive output between two populations from Pacific and Atlantic coasts. Ovigerous females were collected between September and November 2005 in Punta Morales, Pacific coast of Costa Rica (n = 137) and from March 2005 to July 2006 in Araçá region, São Paulo, Brazil (n = 46). The mean size of females was statistically different between both populations with larger females from Brazil than Costa Rica (7.9 ± 1.31 and 6.6 ± 0.95 mm CW, respectively). Likewise, egg production was significantly different in both populations and started in Pacific Costa Rica at a smaller female size than in Brazil. Specimens from Pacific Costa Rica produced roughly three times more eggs than equally sized females from Brazil, while newly extruded embryos were larger in Brazil than in Costa Rica (0.045 and 0.039 mm³, respectively). Egg volume increased during embryogenesis by 112.8 and 164.5% in Costa Rican and Brazilian populations, respectively. The egg water content increased steadily in both populations; however, eggs produced in Brazil contained always more water than those from the same developmental stage in Costa Rica. Average reproductive output (based on dry weight) was substantially lower in Brazil (0.031) than in Costa Rica (0.065). Our results confirm an impressive intraspecific plasticity of reproductive features in an intertidal decapod. The observed phenotypical variability might be related to local environmental conditions as well as to the location of the studied population concerning its geographic range of distribution.     

Effects of temperature on the reproduction and development of Drosophila suzukii (Diptera: Drosophilidae)

The objective of this study was to elucidate how temperature affects the reproduction and development of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), an emerging major pest of blueberry in Japan. Although extensive studies of the biology of this pest have been carried out, the effects of temperature on its reproduction and development remain unknown. We found that when adults mated at 31 °C for 4 days, none of the eggs hatched. Female oviposition and egg hatching rate were also reduced as temperature increased during the oviposition period. When D. suzukii larvae developed above 31 °C, pupation and adult eclosion were abolished. According to field observations, adult D. suzukii ceased to appear from the end of July 2010, when the average temperature exceeded 28 °C or when the temperature within a day exceeded 33 °C for 8 h or more. Experiments in which the mating temperature fluctuated within a day revealed that both the number of eggs oviposited and their hatch rate were significantly suppressed when the daily temperature regime during mating was either 31 °C for 12 h/25 °C for 12 h or 33 °C for 8 h/25 °C for 16 h, relative to the values at 25 °C for 24 h.     

Microsatellite Variability and Its Relationship with Growth, Egg Production, and Immunocompetence Traits in Chickens

Variability of microsatellites and a possible relationship with growth, egg production, and immunocompetence traits were estimated for six crossbred chicken populations of White Leghorn. Nine microsatellite markers were explored; an association study used the least square maximum-likelihood method on 170 birds of six genetic groups. Seven microsatellites were polymorphic, with two to four alleles. The polymorphism information content (PIC) of five markers was more than 52%. Microsatellites MCW0041, ADL0210, and MCW0110 were significantly (P < 0.05) associated with egg production traits. Genotype 33 of MCW0041 had the highest egg production, up to 64 and 72 weeks of age. Genotypes 11 and 13 of this marker produced the lowest number of eggs. The heterozygous genotype 34 of ADL0210 had the highest egg production, up to 52, 64, and 72 weeks of age. Homozygote 11 of MCW0110 produced the highest number of eggs, up to 28 weeks of age. MCW0041 was significantly (P < 0.05) associated with body weight at 28 and 40 weeks of age. No microsatellite was significantly associated with egg weight at any age, with age at sexual maturity, or with immune response to sheep RBC.     

Enzyme-linked immunosorbent assay (ELISA) used in quantification of reproductive output in the pacific oyster,Crassostrea gigas,in Korea

Polyclonal antibody developed from egg proteins of the Pacific oysters, Crassostrea gigas, was used in quantification of the eggs. Quantity of the egg protein was measured using ELISA and a weight-normalized gonadosomatic index (GSI) was then established. Histology indicated that the oysters collected from Goseong Bay, Korea, in 2000 initiated gametogenesis as early as late February and spawned mostly in late June to early July when water temperature reached 23–25 °C. A second spawning peak was also observed in late August and the spawning activity continued to late October. Oyster egg proteins could be detected by ELISA in all months except March and November; a few oysters collected during December and January contained a measurable amount of eggs. The highest monthly mean GSI, 0.423, was observed in mid-June when the oysters were ready to spawn. The maximum GSI recorded in this study was 0.667. A positive correlation was found between oyster size and fecundity; the number of eggs increased as oyster biomass increased (r²=0.7497). Our data suggest that oysters in Goseong Bay produce 3–196 million eggs during the spawning season. The immunological method developed in this study was sensitive enough to measure a small quantity of eggs and considered to be method of choice for studying bivalve reproduction.     

Observations on the epidemiology and interactions between myxomatosis, coccidiosis and helminth parasites in a wild rabbit population in Scotland

A study of the epidemiology of myxomatosis and the protozoan liver parasite, Eimeria stiedae, in a population of wild rabbits in Scotland from 1977 to 2010 is reported. Rabbits were collected on a monthly basis resulting in a total of 5,337 animals examined for the infections. The investigation showed that within any 1 year over the 34 years of the investigation the percentage of rabbits with myxomatosis varied between 0 and 24 %, while for E. stiedae infections fluctuated between 3 and 42 %. There were strong seasonal trends in the prevalence of myxomatosis with over 16 % being infected in September and October, and for E. stiedae, peaks of over 40 % of livers infected were recorded in July. From 2007 to 2010, faeces were also examined for coccidia oocysts and parasitic nematode eggs. Rabbits infected with the myxoma virus had mean oocyst counts of 73,665 per gram faeces, while rabbits not infected with the myxoma virus had counts of 31,952 oocysts per gram. Comparable figures for nematode faecal egg counts were 911 per gram in myxomatosis-infected animals and 427 per gram in uninfected animals. The elevated nematode faecal egg counts in rabbits with myxomatosis reflects increased worm burdens already reported, but the elevated counts of coccidial oocysts have not previously been reported. This would suggest that myxomatosis could compromise rabbit immunity to nematodes and coccidia.     

Description of Immature Stages and Development Time of Paralucilia paraensis (Mello) (Diptera: Calliphoridae) Associated with the Decomposition of a Partially Submerged Swine Carcass

We report on the bionomics and morphology of the immature stages of Paralucilia paraensis (Mello) (Diptera: Calliphoridae). Observations were made on a daily basis for 10 h (from 8 a.m. to 6 p.m.) on a 45-kg pig (Sus scrofa) whose carcass had been partially submerged in a stream of water on the 21st of November 2009, in a forested area of Manaus, Amazonas, Brazil. The collected specimens were placed in plastic vials and transferred to a growth chamber maintained at room temperature. Adults of P. paraensis were collected on the carcass between the 3rd and the 18th days. A total of 13 gravid females were captured; from these, 1,240 eggs were obtained and yielded 1,030 larvae that developed into 879 adults. The average time required for hatching was 13 h. On average, the larvae reached the second instar within 13 h, third instar within 18 h, and pupae within 46 h. The pupal stage lasted 96 h. The complete development time was 216 h. This is the first report on the development time and morphology of immature stages of P. paraensis in forested areas. Therefore, these results provided information for the implementation of future forensic studies in the state of Amazonas.     

An invasive stink bug as an evolutionary trap for an indigenous egg parasitoid

Invasive alien species can act as ‘evolutionary traps’ for indigenous parasites and predators when the alien species is accepted as prey or a host but is unsuitable for consumption or development. We tested the relationship between acceptance and suitability of eggs of the invasive alien Halyomorpha halys (Hemiptera: Pentatomidae) in North America relative to eggs of the indigenous Podisus maculiventris (Pentatomidae) for the indigenous generalist egg parasitoid Telenomus podisi (Hymenoptera: Scelionidae). T. podisi accepted 0–24 h old H. halys eggs at a rate similar to P. maculiventris eggs (87.5 ± 6.0 and 70.2 ± 9.1 %, respectively). Successful development of T. podisi occurred in 98.3 % of attacked P. maculiventris eggs, but was not observed in H. halys eggs. Oviposition by T. podisi did, however, reduce the developmental success of H. halys embryos relative to unattacked controls by 24.1 % in 0–24 h old eggs and 29.6 % in 24–48 h old eggs. We suggest that as H. halys spreads and increases in abundance in North America, it could operate as an evolutionary trap for indigenous egg parasitoids, thereby indirectly causing an increase in population levels of indigenous pentatomids. This predicted indirect effect would be a result of H. halys eggs acting as an egg sink for T. podisi. We also introduce the concept of a ‘time sink’, which may be particularly relevant for parasitoids such as T. podisi that spend considerable time protecting their reproductive investments.     

Early embryonic development and diapause stage in the band-legged ground cricket Dianemobius nigrofasciatus

The band-legged ground cricket Dianemobius nigrofasciatus enters diapause at an early embryonic stage when adults are reared under short-day conditions or the eggs are exposed to a low temperature. We examined the morphological features of the embryo during early development and determined the exact stage of entry into diapause. In non-diapause eggs, no periplasmic space was observed in the surface region and a small number of nuclei surrounded by cytoplasm (energids) were found among the yolk granules and lipid droplets 12 h after egg laying (AEL) at 25°C. The energids sparsely but evenly populated the surface region at 40 h AEL, but there were some gaps between these energids. A continuous thin layer of nuclei with cytoplasm had completely covered the egg surface at 56 h AEL, suggesting that the blastoderm is formed between 40 and 56 h AEL. At 72 h AEL, we found a germ band at the posterior pole. Electron microscopy revealed clear cell membranes at 40 h AEL. Staining with rhodamine-dextran dye demonstrated that the cell membrane is formed when the nuclei appear on the egg surface at 12–24 h AEL. These results indicate that cellularization occurs before blastoderm formation. In diapause eggs, neither the embryonic rudiment nor germ band was formed, but a continuous layer of cells covered the egg surface. It is concluded that D. nigrofasciatus enters diapause at the cellular blastoderm.     

Reproductive biology of the invasive Asian freshwater leech Barbronia weberi (Blanchard, 1897)

Barbronia weberi were collected from Hydrilla verticillata purchased from aquarium suppliers in Melbourne, Australia and additional B. weberi were obtained from aquatic plants in Canberra, ACT, Australia. Adult leeches fed Tubifex sp. ad libitum successfully reproduced under laboratory conditions (21 ± 5?°C ). Reproductively mature B. weberi produced cocoons every week for up to three months at which time the adults began to senesce. Cocoons contained one to five (barx=2.41±0.78 SD, N=58) eggs with juveniles leaving the cocoon within 27 ± 3.4 SD days (N=13) of cocoon production. Juvenile B. weberi reached reproductive maturity within four months (N=7) of hatching and had a maximum growth rate of 1.10 mm² d^?1 once they left the cocoon at around 30 days. Individual egg volume (r=0.63, scaling exponent = 1.21) and cocoon volume (r=0.65, scaling exponent = 1.24) showed a significant (P<0.001) and nearly isometric relationship when scaled with maternal body size. Because this species can grow rapidly and produce a large number of eggs over a short period of time and can piggyback with plant species and travel through the aquarium trade, there is potential for B. weberi to rapidly invade new localities.     

Location and timing of Asian carp spawning in the Lower Missouri River

We sampled for eggs of Asian carps, (bighead carp Hypophthalmichthys nobilis, silver carp H. molitrix, and grass carp Ctenopharyngodon idella) in 12 sites on the Lower Missouri River and in six tributaries from the months of May through July 2005 and May through June 2006 to examine the spatial and temporal dynamics of spawning activity. We categorized eggs into thirty developmental stages, but usually they could not be identified to species. We estimated spawning times and locations based on developmental stage, temperature dependent rate of development and water velocity. Spawning rate was higher in the daytime between 05:00 and 21:00 h than at night. Spawning was not limited to a few sites, as has been reported for the Yangtze River, where these fishes are native, but more eggs were spawned in areas of high sinuosity. We employ a sediment transport model to estimate vertical egg concentration profiles and total egg fluxes during spawning periods on the Missouri River. We did not identify substantial spawning activity within tributaries or at tributary confluences examined in this study.     

The suitability of Ostrinia furnacalis (Lepidoptera: Crambidae) eggs for Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae) can be changed by T. ostriniae

This study compared the host specificity of two Trichogramma species on Corcyra cephalonica (Stainton) and Ostrinia furnacalis (Güenée) eggs. Trichogramma ostriniae Pang et Chen (TO) took more time for oviposition during probing and laying eggs, compared with Trichogramma dendrolimi Matsumura (TD). Furthermore, the proportion of host eggs oviposited actually by TD was lower than that by TO on O. furnacalis eggs, whereas there was no significant difference on C. cephalonica eggs. TO produced more females and total offspring than TD on O. furnacalis eggs. This indicated that O. furnacalis was less suitable for the development of TD, compared with the combination of C. cephalonica and TD or O. furnacalis and TO. Microinjection with 4.0 eq μl^?1 extract of TO female abdomens induced lower hatchability and longer developmental duration of O. furnacalis egg, whereas the extract from TD prolonged developmental duration only slightly, indicating weak toxicity of TD extract. TD emerged from 72.0 % of O. furnacalis eggs helped by oviposition of TO females irradiated with 800 Gy/h ⁶⁰Co for 6 min, of which the intensity produced no TO offspring, whereas only 6.5 % of the eggs were parasitized solely by TD. This indicates that the suitability of O. furnacalis to TD can be increased by the addition of TO parasitization factors.     

Studies ontrichogramma buesi as a biocontrol agent againstPieris rapae in Egypt

Trichogramma buesi was reared in the laboratory on eggs of the Mediterranean flour moth,Anagasta kuehniella. The incubation period of the parasite's egg was 27 h at 23 °C and 22 h at 27 °C. The larval stage lasted 3.6 and 3.2 days, the pre-pupa lasted 16 and 23 h, and the pupa lasted 5.4 and 4.6 days at 23° and 27°C, respectively. The total developmental time (from egg to adult) averaged 9.2, 9.4, and 9.1 days when the parasite was reared on eggs ofPieris rapae, Spodoptera littoralis, andA. kuehniella, respectively, at 27 °C. Sex ratio inT. buesi was 1 ♂: 1 ♀ in nature and 1 ♂: 1.3 ♀ in the laboratory. The daily and total numbers or progeny produced/female were 5.1 and 98.2 adults, respectively. The parasite female, fed on honey, lived 10.7 days at 27 °C and 12.1 days at 23 °C. Percentages of parasitism byT. buesi on eggs ofP. rapae collected from cabbage fields ranged between 0 and 31.5 % in 1985 and betwcen 0 and 36.4% in 1986 during July through December. The respective figures on eggs collected from turnip fields were 16–42.2% and 12.5–32.1% during November and December.      

Effects of Chromium Propionate on Egg Production,Egg Quality,Plasma Biochemical Parameters,and Egg Chromium Deposition in Late-Phase Laying Hens

This study was conducted to investigate the effects of chromium propionate on egg production, egg quality, plasma biochemical parameters and egg chromium deposition in late-phase laying hens. Four hundred thirty-two 60-weeks old laying hens were divided into four groups of 108 birds per group according to egg production. The dietary treatments consisted of the basal diet adding with 0, 200, 400, and 600 μg/kg chromium as chromium propionate. All laying hens were given feed and water ad libitum for 8 weeks. The addition of 400 μg/kg Cr as chromium propionate increased egg production (P?<?0.01) during the later 4 weeks, but decreased albumen height, yolk color score, and Haugh unit of eggs. Six hundred micrograms per kilogram Cr as chromium propionate supplementation improved shell thickness (P?<?0.05). 200 μg/kg Cr as chromium propionate supplementation decreased the uric acid concentration by 31 % (P?<?0.05). However, supplemental Cr did not affect the egg chromium deposition of hens (P?>?0.05). These data indicated that feeding of late-phase laying hens with chromium propionate could improve egg production, increase eggshell thickness, but do not result in abnormal levels of chromium deposition in eggs.     

A phylogenetic analysis of egg size,clutch size,spawning mode,adult body size,and latitude in reef fishes

Theoretical treatments of egg size in fishes suggest that constraints on reproductive output should create trade-offs between the size and number of eggs produced per spawn. For marine reef fishes, the observation of distinct reproductive care strategies (demersal guarding, egg scattering, and pelagic spawning) has additionally prompted speculation that these strategies reflect alternative fitness optima with selection on egg size differing by reproductive mode and perhaps latitude. Here, we aggregate data from 278 reef fish species and test whether clutch size, reproductive care, adult body size, and latitudinal bands (i.e., tropical, subtropical, and temperate) predict egg size, using a statistically unified framework that accounts for phylogenetic correlations among traits. We find no inverse relationship between species egg size and clutch size, but rather that egg size differs by reproductive mode (mean volume for demersal eggs = 1.22 mm³, scattered eggs = 0.18 mm³, pelagic eggs = 0.52 mm³) and that clutch size is strongly correlated with adult body size. Larger eggs were found in temperate species compared with tropical species in both demersal guarders and pelagic spawners, but this difference was not strong when accounting for phylogenetic correlations, suggesting that differences in species composition underlies regional differences in egg size. In summary, demersal guarders are generally small fishes with small clutch sizes that produce large eggs. Pelagic spawners and egg scatterers are variable in adult and clutch size. Although pelagic spawned eggs are variable in size, those of scatterers are consistently small.     

Phenology of annual kelp Eckloniopsis (Phaeophyceae,Laminariales) forest on a Diadema barren in Uchiura Bay,Central Pacific Coast of Honshu,Japan

On the southern coast of Uchiura Bay, central Pacific, Japan, Diadema barrens have expanded since the 1980s but Eckloniopsis radicosa (annual kelp endemic to Japan) has remained in deeper waters (>10 m in depth). Phenology of the kelp was studied on isolated boulders from December 2011 for a year. Young sporophytes appeared in December and rapid growth from April brought the maximum blade length (83.3?±?13.9 cm) and width (56.8?±?12.7 cm) and standing crop (7.4 kg m^?2) in May and June, respectively. Sorus formation began in June and spore release occurred from July to September. Blade length decreased from August and disappeared in November though holdfast remained. The unique holdfast-like spiny ball was found to provide habitats for mobile animals; its forests have an important role to maintain the biodiversity on barrens. During the period, water temperature was between 14.6 and 27.8 °C, salinity was stable around 34–35?‰, and nutrients were never depleted. Tolerance to large and frequent fluctuation of water temperature (7 °C in a day), rapid growth in winter to spring, and occurrence on limited boulders in soft substrata may be the reasons for the success in the maintenance of its forest in Diadema barrens.     

Influence of temperature and light–dark cycle on hatching of <Emphasis Type="Italic">Eylais extendens</Emphasis>

Little research has been done on egg diapause and the embryonic development of water mites. The aim of this study was to check the impact of temperature and periods of light on hatching of larvae of Eylais extendens. Three batches of eggs which were spawned on 30 July were placed at one of three temperatures (4, 10 and 20 °C) and two periods of light (7 and 14 h per day). Egg hatching (both, percentage of hatched larvae and rate of hatching) was found to differ between 4 versus 10 °C and between 4 versus 20 °C, but not between 10 versus 20 °C. The periods of light had no influence on hatching. This synchronization of hatching, enabling the eggs to emerge from diapause in the spring, could be considered an evolutionary adaptation aimed at postponing hatching of late-spawned eggs until a time allowing for completion of the full development cycle, including the parasitic larval stage.     

Biology and Thermal Requirements of <Emphasis Type="Italic">Fopius arisanus</Emphasis> (Sonan, 1932) (Hymenoptera: Braconidae) Reared on <Emphasis Type="Italic">Ceratitis capitata</Emphasis> Eggs (Wiedemann) (Diptera: Tephritidae)

Fopius arisanus (Sonan) is a solitary parasitoid of eggs and the first instar larvae of Tephritidae. Due to the occurrence of Ceratitis capitata (Wiedemann) in various regions and under several climatic conditions, this study aimed to evaluate the effect of different temperatures on the embryonic development (egg–adult) and determine thermal requirements and the number of annual generations F. arisanus on eggs of C. capitata. In the laboratory, eggs of C. capitata (24 h) were submitted to parasitism of F. arisanus during 6 h. Later, the eggs were placed in plastic containers (50 mL) (50 eggs/container) on a layer of artificial diet and packed in chambers at temperatures 15, 18, 20, 22, 25, 28, 30, and 32 ± 1°C, RH 70 ± 10%, and a photophase of 12 h. The largest number of offspring, emergence rate, and weight of adults of F. arisanus were observed at 25°C. The highest sex ratios (sr > 0.75) were recorded at 15 and 18°C, being statistically higher than the temperatures 20°C (0.65), 22°C (0.64), 25°C (0.65), 28°C (0.49), and 30°C (0.47). At 32°C, there was no embryonic development of F. arisanus. The egg–adult period was inversely proportional to temperature. Based on the development of the biological cycle (egg–adult), the temperature threshold (T _t) was 10.3°C and thermal constant (K) of 488.34 degree-days, being the number of generations/year directly proportional to the temperature increase. The data show the ability of F. arisanus to adapt to different thermal conditions, which is important for biological control programs of C. capitata.