Effects of thermoperiods on the reproductive activity of females and on the maternal induction of larval diapause in the blowfly, <Emphasis Type="Italic">Calliphora vicina</Emphasis> R.-D. (Diptera,Calliphoridae)

The interaction of thermoperiod and photoperiod in their influence on the reproductive maturation of females and on the induction of the maternal effect determining larval diapause of the progeny of the blowfly, Calliphora vicina, was first investigated under laboratory conditions. Under the combination of a day length of 12 h with a thermoperiod (the alternation of 12 h long periods with temperatures of 10 and 20°C) the reproductive maturation of females was faster than at the corresponding mean constant temperature of 15°C. Under the “natural” thermoperiod, when the period with a temperature of 10°C coincided with “night-time” (the dark phase of the diurnal light-dark cycle) the maturation of females was slower than that under the “inverted” thermoperiod, when the period with a temperature of 10°C coincided with “day-time” (the light phase of the diurnal light-dark cycle). The proportion of diapausing individuals was maximal in the progeny of females kept at 20°C and decreased with the increase in temperature. Under thermoperiods (the alternations of 12 h long periods with temperatures of 20 and 26°C) the proportion of diapausing progeny was lower than that under the corresponding mean constant temperature of 23°C, but under the inverted thermoperiod with a high night temperature this effect was much stronger. In combination with the results of our previous studies, these data support the hypothesis that the effects of “night” and “day” temperatures are substantially different only when the thermal response interacts with a strong photoperiodic response.     

Effect of food and temperature on the reproduction of the blowfly, <Emphasis Type="Italic">Calliphora vicina</Emphasis> R.-D. (Diptera,Calliphoridae), a popular model object in biological research

Egg maturation in Calliphora vicina is known to occur within a wide range of temperatures, from 12°C to nearly 30°C (Vinogradova, 1991). Photoperiodism has no effect on this process. Some females enter diapause already at 20°C; their fraction increases at lower temperatures and reaches 100% at 6°C. Reproducing females with eggs can survive for a long time and even lay eggs at low temperatures (4–5°C). Experiments with C. vicina from Leningrad Province revealed some effects of the diet (liver or fish) and temperature on the fly reproduction. At 20 and 25°C, 7–10-day old females begin to oviposit, but at 20°C egg maturation is observed in 98% of females feeding on liver and in only 5% of females feeding on fish. On the liver diet, the mean daily fecundity is significantly correlated with the day of oviposition but not with the temperature. At 20°C a significant correlation is observed between the mean daily fecundity and both the day of oviposition and food. The total number of eggs laid by flies after feeding on fish is half that produced after feeding on liver. The optimal conditions for Calliphora vicina cultivation are a 16-h light day, temperatures within the range from 20 to 25°C, and liver as food.     

Color polymorphism,development, and reproductive diapause of the multicolored Asian ladybird <Emphasis Type="Italic">Harmonia axyridis</Emphasis> (Pallas) (Coleoptera,Coccinellidae) females

Preimaginal development and maturation of females of two laboratory strains originated from two populations of the multicolored Asian ladybird Harmonia axyridis were investigated under laboratory conditions. Females of the autochthonous population from Irkutsk (Siberia) enter diapause under the short day conditions, whereas in females of the invasive population from Sochi (the Caucasus) photoperiodic induction of diapause is weak. The two populations also differ in the proportions of morphs: the population from Sochi is represented only by the morph succinea, whereas the population from Irkutsk is represented by the morphs succinea и axyridis with the predominance of the last one, which in our study was separated into two phenotypes, differed in the degree of melanization. Rearing of adults under the short day (12 h) conditions induced reproductive diapause in females of all the studied morphs and phenotypes of the Irkutsk population, whereas under the long day (18 h) conditions females of the morph succinea showed a slightly lower tendency to diapause. Evidently, the interpopulation differences in the responses regulating the seasonal cycle of the multicolored Asian ladybird are determined by genes that are not involved (or almost not involved) in the determination of the color polymorphism. The interpopulation differences in size and weight were quite substantial, whereas the differences between morphs and phenotypes were statistically significant in only some of our experiments. In combination with the literature data, these results suggest that the genes determining the color polymorphism in H. axyridis may have a pleiotropic effect on other traits including important eco-physiological parameters but this effect is relatively weak and manifests itself only against a particular genetic background and / or under particular environmental conditions.     

The influence of temperature,photoperiod, and diet on development and reproduction in the four-spot lady beetle <Emphasis Type="Italic">Harmonia quadripunctata</Emphasis> (Pontoppidan) (Coleoptera,Coccinellidae)

This is the first report on the effects of temperature (from 17 to 30°C), photoperiod (from 10 to 16 h of light), and diet (the wheat aphid Schizaphis graminum and the green peach aphid Myzus persicae) on preimaginal developmental rates, adult body mass, preoviposition period, and female fecundity of the predatory lady beetle Harmonia quadripunctata (Pontoppidan) under the laboratory conditions. A constant temperature of 30°C was lethal to the embryos. Judging from the data obtained at 17, 20, and 25°C, the lower temperature threshold for total egg-to-adult development equaled 12.0°C and the respective sum of effective temperatures was 274 degree-days. Preimaginal development was somewhat faster under short-day conditions, the threshold for this quantitative photoperiodic response being approximately 14 h at the rearing temperatures of 20 and 25°C. At a temperature of 25°C, the mean body mass of newly emerged adults was greater for those individuals that during the larval stage had been fed on the green peach aphid (16.4 mg in males and 18.4 mg in females) than in those fed with the wheat aphid (13.8 mg in males and 15.3 mg in females). The preoviposition period (measured from adult emergence to the first egg laid) also depended on temperature and had a lower threshold of 13.4°C and a sum of effective temperatures of 152 degree-days. Maximum fecundity was observed at 25°C and 16-h day length; under these conditions, the oviposition period lasted over 100 d, and the average lifetime fecundity was about 800 eggs per female. Under short-day conditions, females of H. quadripunctata entered reproductive diapause. The photoperiodic threshold for this qualitative response at the temperatures of 20 and 25°C was about 14 h when fed on the peach aphid and 15 h when fed on the wheat aphid. Relatively small body size, low fecundity, and a strong photoperiodic response that hinders rapid adaptation to novel climates probably explain the fact that H. quadripunctata, in contrast to H. axyridis, has not become an aggressive invader.     

The ontogeny of the oribatid mite <Emphasis Type="Italic">Nanhermannia coronata</Emphasis> (Acari,Oribatida, Nanhermanniidae)

The ontogeny of the oribatid mite Nanhermannia coronata (Oribatida, Nanhermanniidae) was studied in the laboratory. At a temperature of 22–23°C and air humidity 100%, the entire life cycle from egg to adult lasted for 105–124 days. N. coronata juveniles and females are described. The diagnostic characters of the chaetom of N. coronata and N. nana larvae and nymphs are given. Morphological differences between N. coronata and N. nana allow distinguishing these species at all active stages.     

Photoperiodic and temperature control of nymphal development and induction of reproductive diapause in two predatory Orius bugs: interspecific and geographic differences

Abstract The effects of day‐length and temperature on pre‐adult growth and induction of reproductive diapause are studied in Orius sauteri and Orius minutus (Heteroptera: Anthocoridae) from northern (43.0°N, 141.4°E) and central (36.1°N, 140.1°E) Japan. In the north, at 20 °C, pre‐adult growth is slower under an LD 14 : 10 h photoperiod than under shorter or longer photophases. At 24 and 28 °C, the longer photophases result in shorter pre‐adult periods. Acceleration of nymphal growth by short days in autumn appears to be adaptive. In the central region, this response is less pronounced, suggesting that timing of adult emergence is less critical than in the north. Day length also influences the thermal requirements for pre‐adult development. The slope of the regression line representing temperature dependence of pre‐adult development is significantly smaller and the lower development threshold (LDT) is significantly lower under an LD 12 : 12 h photoperiod than under long‐day conditions. The weaker dependence of nymphal growth on temperature and the lower LDT in autumn might be adaptive. In the north, increased temperature shifts the critical day length of diapause induction and suppresses the photoperiodic response in O. sauteri but not in O. minutus. Further south, the incidence of diapause in both species is low even under short‐day conditions but the same interspecific difference is observed (i.e. increase of temperature affects the response in O. sauteri but not in O. minutus). This suggests seasonally earlier diapause induction with weaker temperature dependence in O. minutus than in O. sauteri.     

A review of the history of research and control of <Emphasis Type="Italic">Rhipicephalus</Emphasis> (<Emphasis Type="Italic">Boophilus</Emphasis>) <Emphasis Type="Italic">microplus</Emphasis>, babesiosis and anaplasmosis in Uruguay

The effect of five constant temperatures (16, 20, 24, 28 and 32 °C) on the development, survival and reproduction of Tetranychus cinnabarinus (Boisduval) [=?Tetranychus urticae Koch (red form)] fed on cassava leaves was examined in the laboratory at 85% relative humidity. Development time of various immature stages decreased with increasing temperature, with total egg-to-adult development time varying from 27.7 to 6.7 days. The lower thermal threshold for development was 10.8 °C and the thermal constant from egg to adult was 142.4 degree-days. Pre- and post-oviposition period and female longevity all decreased as temperature increased. The longest oviposition period was observed at 20 °C with 20.4 days. Under different temperatures, mated females laid, on average, 1.0, 2.9, 4.7, 4.7 and 4.9 eggs per day, respectively. The maximum fecundity (81.5 eggs per female) was at 28 °C and the intrinsic rate of increase (r _m ) was highest (0.25) at 32 °C. The results of this study indicate that T. cinnabarinus population could increase rapidly when cassava leaves serve as a food source. At the appropriate temperature T. cinnabarinus could seriously threaten growth of cassava.     

Specific features of distribution and some features of biology of Korean flounder <Emphasis Type="Italic">Glyptocephalus stelleri</Emphasis> (Pleuronectidae) in waters off Kamchatka in the Sea of Okhotsk

According to materials of 1997–2002, the characteristic of the spatial-bathymetric distribution, size and age composition, size and sex structure, and feeding of the Korean flounder Glyptocephalus stelleri in the summer period in waters off Kamchatka in the Sea of Okhotsk (the site from 51°15′ to 57°20′ N, depths of 10–300 m) is given. It is shown that throughout the observation period, maximum catches of this flatfish were constantly observed at two sites of the western Kamchatka shelf (51°20′–53°00′ N and 55°00′–56°00′ N) in the zone exposed to the effect of anticyclonic gyres in the range of depths 101–200 m at the near-bottom temperature below 2°C. Unlike other habitat areas, off the coast of western Kamchatka, G. stelleri in the summer time is quite frequently found at negative temperature values, which is obviously determined by the specifics of thermal conditions of the eastern part of the Sea of Okhotsk. It was established that, in this species of flatfish, sex dimorphism is distinctly pronounced in sizes—males are considerably smaller than females whose relative number among individuals with a length larger than 50 cm reaches 100%. The main items of feeding of G. stelleri at the western Kamchatka shelf in the summer period are oligochaetes.     

Life history parameters of two geographically separated populations of <Emphasis Type="Italic">Spalangia cameroni</Emphasis>, a microhymenopteran pupal parasitoid of muscoid flies

Spalangia cameroni Perkins (Hymenoptera: Pteromalidae) is used as a biological control agent against house flies and stable flies in livestock farms in Northern Europe. In the present study, the juvenile development, survival, and sex ratio of one Danish and one Norwegian population of S. cameroni were investigated at 15, 20, 25, 30, and 35°C to determine the best adapted strain for release programs. The Danish population developed 50 days faster at 15°C, whereas the Norwegian developed 3–4 days faster at 25°C. The difference was smaller at 20°C and 30°C. Only a few Danish female parasitoids emerged at 35°C. Both populations required 381 degree days to complete development and exhibited optimal juvenile survival at 23.7°C. The Norwegian population produced more females than the Danish population at all temperatures (average of 67.5% vs. 55.5%, respectively). The overall differences between the populations were small, but might still be important for inundative release programs.     

Development of the Taiga Tick <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> Schulze, 1930 Population under Laboratory Conditions

The dynamics of development of the population of taiga ticks Ixodes persulcatus Schulze, 1930 from Eastern Siberia was studied under experimental conditions. Ticks were reared at 23–25°C, relative humidity of 80–90%, and a light: darkness ratio of 16: 8 h. The mean time of egg incubation was 35.2 days; the feeding of females, larvae, and nymphs took 6.4, 3.5, and 4.5 days, respectively. The existence of two subpopulations, differing in the time of development of engorged larvae into nymphs and nymphs into adults, was experimentally demonstrated. Most ticks had short periods of larval and nymphal development that lasted 25 ± 2 and 40 ± 4 days, respectively. However, some ticks exhibited prolonged development time of 75.5 ± 2 and 95 ± 9 days, respectively. The total duration of the life cycle was 121 days in the former group and 226 days in the latter group.     

The Influence of Diet and Population Density on Maturation of Females from Native and Invasive Populations of the Multicolored Asian Ladybird <Emphasis Type="Italic">Harmonia axyridis</Emphasis> (Pallas) (Coleoptera,Coccinellidae)

Population density can influence insect reproduction both directly and indirectly causing quantitative and qualitative changes in the feeding regime. We investigated the impact of diet and population density on reproductive maturation of females from native (Irkutsk) and invasive (Sochi) populations of the multicolored Asian ladybird Harmonia axyridis. During the study the beetles fed either on the green peach aphid, Myzus persicae, or on less suitable factitious food (eggs of the grain moth Sitotroga cerealella). Population density was determined by the number of females and males placed in a standard Petri dish. The experiments showed that feeding on the grain moth eggs (other conditions being equal) delayed maturation and increased the tendency to enter reproductive diapause in females from the native but not from the invasive population of H. axyridis. In addition, the preoviposition period increased with the number of females but decreased with the number of males in a dish, although these effects were observed only in individuals from the invasive population and their strength depended on the food of the beetles. Earlier we have demonstrated that the impact of the density-dependent factors on the larvae of the invasive population of H. axyridis was stronger than that on the larvae of the native population because the larvae of the invasive population have somewhat more aggressive interactions with competitors. In the present study, similar differences were revealed between females of these populations.     

Catching of Greenland halibut <Emphasis Type="Italic">Reinhardtius hippoglossoides</Emphasis> (Pleuronectidae) on the shelf edge of the Laptev and East Siberian Seas

The first capture of the Greenland (or Black) halibut Reinhardtius hippoglossoides in the Arctic Ocean on the border with the East Siberian Sea (79°03′–79°08′ N 139°59′–141°16′ E, 259–277 m) and the repeated findings of the species in the Laptev Sea (78°03′–78°04′ N 132°56′–133°04′ E, 307 m; 78°33′–78°35′ N 138°44′–138°48′ E, 125 m) are reported. Fish (79 specimens with the length of 15.0–44.5 cm) were caught during four bottom trawlings on the edge of the continental shelf of the two seas in the transformed waters of Atlantic origin, as evidenced by the discovery of the indicator species of these waters—the Glacier lanternfish Benthosema glaciale (Myctophidae)—in one of the stomachs of halibut. The other captures of Greenland halibut in the Arctic were also reviewed.     

Adaptive responses of embryos and larvae of the heart-shaped sea urchin <Emphasis Type="Italic">Echinocardium cordatum</Emphasis> to temperature and salinity changes

The combined effects of temperature (8, 12, 14, 17, 20, 22 and 25°C) and a salinity decrease from 36 to 12‰ on the development of the sea urchin Echinocardium cordatum (Pennant) were studied. Embryonic development proved to be the process most vulnerable to a salinity decrease. It was completed successfully at 8–20°C within a narrow salinity range of 36–28‰ Larvae at the most resistant stage, the blastula, survived at 12–22°C and a salinity of 36–18‰. Larvae at the most sensitive stage, pluteus I with the first pair of arms, died even in a favorable environment, a temperature of 17–20°C and a salinity of 34–28‰. That may be related to qualitative alterations during skeleton formation and to transition to phytoplankton feeding. The resistance of larvae to variations in environmental factors gradually increased in the pluteus II and III stages; however, it significantly decreased before the settling of the larvae. Larvae that were 37 days old survived at a temperature of 14–20°C within a salinity range of 36–22‰ and at 22 and 25°C, they survived at a salinity of 36–24‰; however, all the larvae became abnormal at 25°C. The larvae settled earlier on sand inhabited by adult individuals of E. cordatum than on sand from other locations, and they settled faster at 20–25°C, than at 14 and 17°C. The juveniles, if lacking an opportunity to burrow in the sand, died within 14 days after settling.     

Seasonal development of the blowfly <Emphasis Type="Italic">Caliphora vicina</Emphasis> R.-D. (Diptera,Calliphoridae) in the environs of St. Petersburg

Four-year monitoring of phenology of the blowfly Caliphora vicina under quasi-natural conditions in the environs of St. Petersburg demonstrated development of two complete generations and overwintering of the third generation. The duration of preimaginal development (from egg laying to adult emergence) of the 1st and 2nd generations varied from 19 to 32 days; the required sum of effective temperatures (SET) was 326 ± 31 degree-days with a threshold of 5°С. Reproductive maturation of females (the period of time from adult emergence to laying of the first eggs) lasted from 15 to 31 days (SET was 262 ± 39 degree-days with a threshold of 5°С). The duration of development of one complete generation (from egg stage to the beginning of oviposition) during the period of observation varied from 34 to 57 days (SET was about 600 degree-days with a threshold of 5°С). The first diapausing larvae hatched from the eggs laid in the middle of August. In September, at shorter day lengths and at a temperature of 10–11°С, 80–100% of the larvae entered diapause. A small fraction of the larvae of the 1st and 2nd generation and most of the larvae of the 3rd generation overwintered. Successful overwintering of adults in the environs of St. Petersburg is hardly possible.     

Nymph and Adult Biology of <Emphasis Type="Italic">Euschistus cornutus</Emphasis> Dallas: a Potential Soybean Pest in the Neotropics

Laboratory studies with Euschistus cornutus Dallas indicated that nymphs complete development when feeding on green bean, Phaseolus vulgaris L. pod, on soybean, Glycine max (L.) Merrill pod, and on raw shelled peanut, Arachis hypogaea L., but not on fruit (berry) of privet, Ligustrum lucidum Ait. Total mortality was lower on green bean pod (45%), and higher on soybean pod and peanut raw (75 and 80%, respectively). Nymph developmental time was significantly longer for females feeding on green bean pod (37.4 days) than on soybean pod (27 days); a single data was observed on peanut raw (32 days). Males showed no significant differences in total nymph developmental time among foods (31.3 to 33.0 days). At adult emergency, fresh body weight of females (52.2 to 68.5 mg) and males (61.9 to 71.3 mg) did not show statistical differences among foods tested nor between genders. Survivorship of E. cornutus adult after 50 days was greater on peanut raw than on green bean or soybean pod; on privet berry, the majority of males and females (>80%) were dead after 20 days. The reproductive performance data was, in general, greater on peanut raw than on green bean or soybean pod; on privet fruit, no female laid eggs. Fresh body weight gain occurred on all foods, except on privet berry, on which adults lost weight over time. Records of specimens from insect collections in Brazil indicated that E. cornutus occurs in the Southeast and South regions (19° to 31° S latitude). The most common host plant is soybean, suggesting a potential pest status of this stink bug on this crop in the future.     

Species specificity in photoperiodic control of nymphal development in four species of cricket from north-west China

Photoperiodic regulation of nymphal development was examined in four species of cricket collected in the Xinjiang‐Uygur Autonomy Region, China (approximately 43°N, 81–89°E). Fifty percent of individuals of Modicogryllus frontalis reared at 28°C reached adulthood in approximately 80 days in conditions of 11 h light : 13 h dark (LD 11:13) to 14:10, and in approximately 95 days under LD 15:9 to 16:8. Melanogryllus desertus started adult emergence earliest under LD 16:8 at 28°C, but some individuals required much longer to mature, and thus two peaks of adult emergence occurred at approximately 60 and 160 days after hatching. More individuals hatched during the late peak in LD 18:6 than in LD 16:8. The mean nymphal period was approximately 100 days in LD 11:13 to 14:10. Both species showed short‐day type photoperiodic responses, but Mo. frontalis developed faster than did Me. desertus. The latter occupied a wider range of habitat conditions and was more variable in life cycle than the former. Modicogryllus burdigalensis started adult emergence earliest in LD 16:8 at 28°C in the six photoperiods tested, most adults emerging within 60 days. The mean nymphal period was 80 days in LD 15:9, 135 days in LD 14:10 and 80–100 days in LD 11:13 to 13:11, showing an intermediate type of photoperiodic response. Acheta domesticus was a long‐day type species, and the proportion of delayed individuals increased with decreasing photoperiod. In the dry climate of Xinjiang‐Uygur, nymphal overwintering seems to be successful in all of the four different patterns of nymphal development.     

Collection and aging of greater amberjack <Emphasis Type="Italic">Seriola dumerili</Emphasis> larvae and juveniles around the Penghu Islands,Taiwan

To investigate the early life history of Seriola dumerili, we first validated otolith daily increments using reared fish (11–51 days after hatching). Four larval and early-juvenile S. dumerili were collected in May and July 2015 around the Penghu Islands, Taiwan (23.45–23.70 °N, 119.40–119.70 °E), by surface larval net towing, but not from drifting seaweeds. Seriola dumerili were caught at the thermal front, and the total lengths and ages ranged 7.4–42.5 mm and 18–56 days, respectively. Our results indicate that the hatching dates of S. dumerili were April to June and larvae may have been accumulated in the frontal zone before the juvenile phase.     

Peculiarities of development in the marine brown alga <Emphasis Type="Italic">Alaria angusta</Emphasis> Kjellman, 1889 (Alariaceae: Ochrophyta) under laboratory-controlled conditions

This paper describes the formation of gametophytes and the early stages of the development of sporophytes in the kelp seaweed Alaria angusta from Kamchatka. To establish laboratory cultures we used zoospores obtained from A. angusta sporophytes collected on October 29, 2014. The gametophytes were grown under different conditions: at 6–7°С and natural light and at 10°С and illumination with cool white fluorescent bulbs, 30 μmol photon m^–2 s^–1, 12: 12 h L: D cycle. In the first case (natural light, 6–7°С), the vegetative growth of male and female gametophytes lasted for more than 4 months; maturation of sexual products occurred 144 days after germination of the embryospores. In the second case (artificial light, 10°С), rapid development of the gametophytes occurred; the first juvenile sporophytes appeared on the 10th day after the zoospores settled onto the substrate. Our data contribute to understanding of the regulatory effect of temperature and light on the peculiarities of species vegetation in the natural environment and formation of the age structure of the species population, one particular feature of this process is the continuous appearance of juvenile sporophytes in the warm period of the year.     

Temperature-dependent ovariole and testis maturation in the yellow dung fly

Temperature is one of the abiotic environmental factors most strongly affecting animal behaviour, physiology, and life history. In insects, lower temperatures generally slow down most physiological processes, reducing growth rate and prolonging the juvenile period. Here, we investigate temperature‐dependent ovariole and testis maturation in the anautogenous yellow dung fly, Scathophaga stercoraria L. (Diptera: Scathophagidae), and relate it to corresponding temperature effects on pre‐adult development time and the adult pre‐reproductive period. Flies were reared in the laboratory at three constant temperatures (18, 22, and 26 °C), and the size of the developing ovarioles and testes (reflecting sperm production) was measured over time (i.e., age). Ovariole size increased asymptotically over the first 12 days of adult life, while the testes continued to fill after day 10. In accordance with the temperature‐size rule, warmer temperatures resulted in smaller ovarioles (eggs) and smaller testes, independent of body size. Warmer temperatures also greatly reduced pre‐adult development time by more than half, from 12 to 25 °C, the larger males always taking 1–3 days longer than the females. Corresponding temperature effects on the adult pre‐reproductive period were small (<1 day between 15 and 25 °C), with males taking 5–6 days and females 10–13 days to first reproduction. Time lost by males during the pre‐adult stage, when ovaries and testes are produced, can thus be more than compensated‐for by time gained during the pre‐reproductive period, when eggs and sperm are produced, so males can nevertheless start reproducing sooner than females.     

Heterotrophic activity of bacterioplankton along the gradients of the chlorophyll <Emphasis Type="Italic">a</Emphasis> concentration and water temperature in marine and limnetic ecosystems

The dependence of the heterotrophic activity of bacterioplankton (V, μg C L^–1 h^–1) on the concentration of chlorophyll a (Chl, μg L^–1) and the water temperature (T) was examined for lakes (37°29′–80°36′ N) and marine polar waters (69°16′–80°36′ N). It was shown that ~76% of the V variations was related to changes in Chl and T.