Diet Affects the Temperature-Size Relationship in the Blowfly Aldrichina grahami.

In warmer environments, most ectotherms exhibit a plastic reduction in body size (the temperature-size rule, TSR). However, in such environments, growth is usually accelerated and would be expected to result in maturation at a larger body size, leading to increases in fecundity, survival, and mating success, compared to maturation at a smaller size (the 'life-history puzzle'). To explore these mechanisms, we reared Aldrichina grahami at 20 °C, 25 °C, and 30 °C, and added a nutritional challenge by using dilutions of pork liver paste to provide diets that ranged in quality from high (undiluted) to moderate (1/8), low (1/16), and poor (1/24). Larvae were randomly sampled for weighing from hatching. Growth curves were fitted to the relationships between growth rate and weight for the third instar larvae. Our results showed that body size was affected by an interaction between temperature and diet, and that following or not following the TSR can vary depending on underfeeding. Moreover, when the TSR was followed as temperature increased, there was a cross-over point that divided the two growth curves into early and later stages, which could be used to help understand the life-history puzzle in warmer temperatures, with the instantaneous growth rate being faster in the early stages of development and then slower in later stages. This study reminds us that animals have evolved to cope with multiple simultaneous environmental changes, and it has thus offered a better understanding of life-history puzzles.

Review of 43 spider species from Hainan Island, China (Arachnida, Araneae).

Photographs of the type specimens of nine spider species described by Barrion et al. (2013) from Hainan Island, China, considered as valid taxa in this study, are provided. Among them, three new combinations are proposed: Clubiona pandalira (Barrion-Dupo, Barrion & Heong, 2013) comb. nov. (ex Nusatidia Deeleman-Reinhold, 2001); Dictis edwardsi (Barrion, Barrion-Dupo & Heong, 2013) comb. nov. (ex Scytodes Latreille, 1804); and Nesioneta mingshengzhui (Barrion, Barrion-Dupo & Heong, 2013) comb. nov. (ex Meioneta Hull, 1920). Thirty-one new synonyms are proposed and three species are considered as nomina dubia.

Tea saponin reduces the damage of Ectropis obliqua to tea crops, and exerts reduced effects on the spiders Ebrechtella tricuspidata and Evarcha albaria compared to chemical insecticides.

BACKGROUND: Tea is one of the most economically important crops in China. However, the tea geometrid (Ectropis obliqua), a serious leaf-feeding pest, causes significant damage to tea crops and reduces tea yield and quality. Spiders are the most dominant predatory enemies in the tea plantation ecosystem, which makes them potentially useful biological control agents of E. obliqua. These highlight the need for alternative pest control measures. Our previous studies have shown that tea saponin (TS) exerts insecticidal activity against lepidopteran pests. Here, we investigate whether TS represents a potentially new alternative insecticide with no harm to spiders. METHODS: We investigated laboratory bioactivities and the field control properties of TS solution against E. obliqua. (i) A leaf-dip bioassay was used to evaluate the toxicity of TS to 3rd-instar E. obliqua larvae and effects of TS on the activities of enzymes glutathione-S-transferase (GST), acetylcholinesterase (AChE), carboxylesterase (CES) and peroxidase (POD) of 3rd-instar E. obliqua larvae in the laboratory. (ii) Topical application was used to measure the toxicity of 30% TS (w/v) and two chemical insecticides (10% bifenthrin EC and 50% diafenthiuron SC) to two species of spider, Ebrechtella tricuspidata and Evarcha albaria. (iii) Field trials were used to investigate the controlling efficacy of 30% TS against E. obliqua larvae and to classify the effect of TS to spiders in the tea plantation. RESULTS: The toxicity of TS to 3rd-instar E. obliqua larvae occurred in a dose-dependent manner and the LC50 was 164.32 mg/mL. Activities of the detoxifying-related enzymes, GST and POD, increased in 3rd-instar E. obliqua larvae, whereas AChE and CES were inhibited with time by treatment with TS. Mortalities of E. tricuspidata and E. albaria after 48 h with 30% TS treatment (16.67% and 20%, respectively) were significantly lower than those with 10% bifenthrin EC (80% and 73.33%, respectively) and 50% diafenthiuron EC (43.33% and 36.67%, respectively). The highest controlling efficacy of 30% TS was 77.02% at 5 d after treatment, which showed no difference to 10% bifenthrin EC or 50% diafenthiuron SC. 30% TS was placed in the class N (harmless or slightly harmful) of IOBC (International Organization of Biological Control) categories for natural enemies, namely spiders. CONCLUSIONS: Our results indicate that TS is a botanical insecticide that has a good controlling efficacy in E. obliqua larvae, which suggests it has promise as application in the integrated pest management (IPM) envisaged for tea crops.

The spectral transmission of non-salticid spider corneas.

Although many salticid spiders have been shown to have corneas that transmit ultraviolet (UV) light, whether the corneas of non-salticid spiders transmit UV has not been previously investigated. In this study, we determined the spectral corneal transmission properties of 38 species belonging to 13 non-salticid families. We used these data to estimate the T50 transmission cut-off value, the wavelength corresponding to 50% maximal transmission for each species. The corneas of almost all species from the families Deinopidae, Lycosidae, Oxyopidae, Pisauridae, Sparassidae and Thomisidae, all of which have been reported to rely to a substantial extent on vision, transmitted short wavelength light below 400 nm, ranging from 306 to 381 nm. However, species from the families Atypidae and Ctenizidae are not known to rely substantially on vision, and the corneas of these species tended to absorb light of wavelengths below 380 nm, which may not allow UV sensitivity in these spiders. Liphistiidae, the family widely regarded as most basal among spiders, is of particular interest. The species in this family are not known to make substantial use of vision, and yet we found that liphistiid corneas transmitted UV light with a low T50 value (359 nm). T50 values of non-salticid spider corneas also varied with light habitat. Species living in dim environments tended to have UV-opaque corneas, but species inhabiting open areas had UV-transmitting corneas. However, there was no evidence of corneal transmission properties being related to whether a species is diurnal or nocturnal.

Imidacloprid affects Pardosa pseudoannulata adults and their unexposed offspring.

Imidacloprid is a nicotine-based, systemic, widely used insecticide. In order to investigate the effects of imidacloprid on the spider Pardosa pseudoannulata (Araneae: Lycosidae), specimens were exposed to different concentrations of imidacloprid (12.5, 25, 50, 100, 200 mg/L) by the dipping method. Surviving spiders were used to determine the fecundity, development time of unexposed offspring, predation, and the activities of detoxification enzymes. Significant reductions were observed in survival rate and fecundity of spiders exposed to imidacloprid. The development times of unexposed offspring (F(1)) were prolonged significantly with increased concentrations of imidacloprid. Spiders exposed to concentrations of imidacloprid above 25 mg/L showed significantly weaker predation on Drosophila melanogaster than the control group, but a low dose of imidacloprid (12.5 mg/L) increased predation ability. The activities of carboxyl esterase, acetyl cholinesterase, and the mixed-function oxidase were significantly inhibited by imidacloprid. With increasing concentrations of imidacloprid, the activities of all three kinds of enzymes were decreased significantly. These results suggest that imidacloprid can stimulate the performance of spiders (in low concentration) and has chronic toxicity to the spiders.