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This study aimed to identify fundamental information regarding the flight dispersal of Eysarcoris aeneus (Scopoli). We investigated the seasonal fluctuations in starvation tolerance, nutritional levels, flight muscles, and ovary development in adult individuals collected from weedy and paddy fields in Ishikawa Prefecture, Japan. Female and male adults exhibited a mean survival period of 2.03 and 1.84 days, respectively, under no water and no feeding conditions at 25°C. New adults exhibited higher starvation tolerance than overwintered adults. The nutritional status was most favorable for overwintered adults in May but declined after June. Overwintered adults had more favorable nutritional status than new adults. Flight muscle development in females varied markedly with the season. A high proportion of individuals had mature ovaries from late May to mid-June, whereas a mixture of mature and immature individuals was observed after July. Based on the physiological status of flying and nonflying E. aeneus individuals, no difference was observed in the nutritional levels among overwintered adults, and flight occurred in individuals with more advanced ovary development. However, there were no differences in ovary development among new adults, and flight occurred in individuals with poor nutritional levels. In conclusion, compared with overwintered adults, new E. aeneus adults displayed physiological characteristics that were associated with dispersal. [ABSTRACT FROM AUTHOR]

Little is known about the social systems of primates at the local population level. For a better understanding of the matter, African great apes are appropriate subjects because many studies have investigated multiple neighboring groups. Here, I reviewed patterns of dispersal, extra-group paternity, and intergroup relationships in African great apes. These three topics are relevant to the three components of primate social systems defined by Kappeler & van Schaik (2002): social organization, mating system, and social structure, respectively. Patterns of female dispersal are similar among African great apes, in that females usually immigrate into groups near their natal groups. In contrast, patterns of male dispersal, often observed in gorillas, are more variable; some males stay near their natal groups after dispersal while others disperse far from their natal groups. Extra-group paternity is rare in African great apes. This is likely because males actively guard females against extra-group males due to severe male-male reproductive competition. Furthermore, extra-group paternity is considered to be disadvantageous in male-philopatric species, as it weakens the degree of kinship among philopatric males within groups. Intergroup male-male relationships are typically antagonistic due to resource defense, although male gorillas sometimes show high degrees of tolerance toward extra-group males. In contrast, intergroup female-female relationships are much more tolerant and affinitive, likely because females typically remain near their natal groups even after dispersal, so that females of neighboring groups are sometimes related to each other. This review highlights that dispersal in both sexes and a scarcity of intergroup breeding shape the kin structure of local populations, which contributes to regulating intergroup relationships in African great apes. Future behavioral and genetic studies that target multiple neighboring groups and dispersing individuals are required to further develop our understanding of primate societies at the local population level. [ABSTRACT FROM AUTHOR]

Bradysia odoriphaga Yang and Zhang (Diptera: Sciaridae) was discovered in the Welsh onion fields of northern Saitama in 2014 and the carrot fields of northern Saitama in 2015, and later in Chinese chive fields in central Gunma Prefecture. Elucidation of the dispersal ability of B. odoriphaga is important for its control. We investigated the flight and walking activities of B. odoriphaga and B. impatiens (Johannsen). The flight and walking durations of adults at 16, 19, 24, and 30°C were investigated by video recording. The flight duration of B. odoriphaga was significantly shorter than that of B. impatiens. In females of B. odoriphaga, the longest continuous flight duration was 2.4 seconds. The walking durations of male B. odoriphaga adults and both sexes of B. impatiens adults were not affected by temperature. In females of B. odoriphaga, the walking durations at 19 and 16°C were significantly shorter than those at other temperatures. Our results suggest that the range of B. odoriphaga dispersal is narrow. [ABSTRACT FROM AUTHOR]

Ecological characteristics of the perilla rust mite, Shevtchenkella sp., that causes damage to Perilla frutescens (Lamiaceae) were studied under a range of temperatures. The mean generation times were 27.3, 15.4, 11.3, 8.8, and 7.8 days at 18, 21, 24, 27, and 30°, respectively. The estimated lower thermal threshold was 12.8°, and the thermal constant for egg-to-egg development was 133.5 degree-days. The intrinsic rate of natural increase (rm) was 0.1001, 0.1504, 0.2020, and 0.2146 at 21, 24, 27, and 30°, respectively. The rm value was not calculated at 18° as more than 70% of the mites failed to reach adulthood, and of those that did, only 2.6% laid eggs. Zero fecundity was estimated at 12.8° based on regression analysis performed using the average number of eggs per female per day. Most females reared with a 13 h photoperiod at 21° in the laboratory were in diapause. The population of the perilla rust mite used in these tests in the laboratory was collected from Kochi Prefecture, Japan. Fifty percent of the diapause females of the perilla rust mite collected from the field in Tokyo in 2015 were forecasted to appear in early October. The nymphs and adults were trapped outside two greenhouses on glass slides coated with high-vacuum silicone grease in Kochi Prefecture throughout the year, indicating that perilla rust mites disperse through air. [ABSTRACT FROM AUTHOR]