A gregarine parasite ofLeptothorax ants from North America

Summary A gregarine parasite (Neogregarinida, Ophryocystidae) ofLeptothorax ants was found near West-Yellowstone, Montana, USA. Infested pupae are characterized by grey to black coloration, irregular pigmentation of compound eyes, and toothless mandibles. The pathogenic effects closely resemble those in the fire ant,Solenopsis geminata, when infested byMattesia geminata. Infested pupae die. The infection can be transmitted to healthy colonies and to differentLeptothorax species by feeding them with infested pupae.     

Habitat structure,dispersal strategies and queen number in two boreal Leptothorax ants

In two nearctic ants, Leptothorax canadensis and Leptothorax sp. A, young queens may either found their own nest solitarily after mating or seek adoption into an established colony. Whether a queen disperses or not is associated with genetically determined queen morphology in Leptothorax sp. A. Whereas a majority of winged queens attempt solitary colony founding after mating, most wingless, intermorphic queens return to their maternal nests and new colonies are founded by budding after hibernation. The latter strategy appears to be correlated with patchy, isolated habitats, whereas in extended boreal forests dispersal on the wing is probably more common. Alternative dispersal strategies strongly affect the average number of queens per colony and seasonal fluctuations of colony structure.     

Social organization in some primitive Australian ants. I.Nothomyrmecia macrops Clark

Summary Results of laboratory-based ethological studies on twoNothomyrmecia macrops colonies with individually marked workers are reported. Interactive behavioural acts constituted less than 1% of all those recorded, revealing a strong tendency by the ants not to engage in social contact. Very few workers performed queen-directed acts. They stayed near the queen, though seldom in direct contact. Division of labour was otherwise barely apparent, except that some individuals showed a propensity to guard the nest entrance. No exchange of food was observed between workers, workers and queen, or adults and larvae (apart from worker placement of prey items with larvae). A queen fed from aDrosophila carcass retrieved from the nest floor, without assistance from workers. Systematic scanned observations confirmed levels of inactivity higher than previously observed in ants (comprising almost 2/3 of recorded behavioural acts). The time budget for activities directed toward the immature stages was the same in both colonies, and fluctuated during the circadian period. Non-nestmate larvae added to worker groups were more frequently licked than nestmate larvae, but this might not involve the particular recognition of nestmateversus non-nestmate brood. These observations support the hypothesis thatNothomyrmecia is primitively eusocial, and of special significance in myrmecology.     

Loss of GH3 function does not affect phytochrome-mediated development in a moss, Physcomitrella patens

Auxin-induced gene expression is described for a variety of different genes including the SAUR-, Aux/IAA- and GH3-families, members of which have been found in seed plants. The precise function of GH3-like proteins in plant development is not well characterised yet. Mutant analysis in Arabidopsis thaliana indicates a possible role for GH3-like proteins in connecting auxin and light signal transduction. Here, we report the isolation of three different GH3-like homologues from a lower land plant, the moss Physcomitrella patens. Two of the GH3-like homologues were chosen for further characterisation. Both genes are expressed in gametophytic tissues, with expression starting very early in moss development. Knockout plants were generated and analysed. In comparison to white-light growth, cultivation of the wild type and knockout plants under red-light conditions resulted in a delay in gametophytic tissue development. The leafy moss plants displayed an elongated phenotype. Growth delay and elongation were even stronger under far-red light conditions. No obvious differences between wild type and knockout plants could be detected under the examined conditions, indicating functional redundancy of the two genes.     

Handling does not affect reproductive signals of male threespine stickleback

We examined the affect of handling on reproductive signal expression in male threespine stickleback, Gasterosteus aculeatus. Spectrophotometric techniques have become popular methods for measuring fish color, but the measurements require handling of the subjects in order to make measurements. Fish can undergo rapid physiological color change in response to stress. As such, handling fish may induce color changes and measured colour may not be representative of signal appearance under non-stressful conditions. We measured the reflectance characteristics of the opercular, ventro-lateral and dorso-lateral areas of 41 reproductive males from Hotel Lake, BC, Canada using spectroradiometry immediately upon capture and again at 2, 3, 4, 5, 10, 15, and 20 min post-capture. Repeated measures ANOVA revealed that post-capture handling did not affect opercular or ventro-lateral reflectance characteristics over the 20 min period. However, we did observe a change in dorso-lateral reflectance characteristics of parental males over the experiment. The results of our study show that handling does not influence reflective properties of two key components of stickleback reproductive signals during a time frame that is reasonable for taking field measurements of signal color.     

Polymorphism in aDrosophila indirect flight muscle-specific tropomyosin isozyme does not affect flight ability

We describe polymorphism in aDrosophila indirect flight muscle-specific tropomyosin isozyme, named TnH-34. Three variants of this protein differ in their mobilities as determined by 1-D and 2-D SDS-PAGE. Meiotic mapping places the polymorphism close to, if not within, the structural gene encoding this tropomyosin isozyme. The most likely site of the mutations is within a single C-terminal exon. Flight-testing of different genotypes reveals that this variation in TnH-34 does not affect flight ability. These results suggest that some sequence variation may be tolerated in this section of the protein and correlate with the variability of this protein in different insect species. This work was supported by an SERC studentship to R.M.C. and SERC Research Grant GR/F17827 awarded to J.C.S. and Dr. David White.     

wzzE不影响禽致病性大肠杆菌雏鸭分离株LPS的表型北大核心CSCD

【目的】wzz参与很多革兰氏阴性菌O抗原的合成,并对细菌的致病性具有调控作用。在禽致病性大肠杆菌（Avian pathogenic Escherichia coli,APEC）中,存在Wzz蛋白超家族基因wzz E,目前尚未开展该基因对APEC脂多糖（LPS）的合成及致病作用研究,因此本研究开展了wzz E对APEC LPS合成以及生物学特性影响的研究。【方法】通过构建APEC DE17株的wzz E缺失株,开展对野生型和缺失株的LD50、黏附与入侵DF-1细胞、脂多糖表型及内毒素毒价等相关生物学特性的影响研究。【结果】结果表明,缺失wzz E的APEC,不影响细菌的生长特性。野生型、缺失株及回复株的LPS表型无明显差异。DE17Δwzz E与DE17的黏附与入侵结果无显著差异。血清型鉴定结果表明,缺失wzz E,不影响细菌的血清型。内毒素毒力检测结果DE17、DE17Δwzz E及CΔwzz E内毒素的毒价一致,为4×10~5 EU/mg。对7日龄樱桃谷鸭进行攻毒,测定各菌株的LD50,结果表明,与野生型相比,DE17Δwzz E缺失株毒力下降了10倍。【结论】wzz E缺失对LPS的表型无显著影响,但wzz E参与APEC的致病过程,然而wzz E对APEC毒力的调控机制仍有待进一步研究。     

Development of a chemically defined diet for ants

A chemically defined diet is a useful tool for the study of nutritional physiology of organisms. We have developed such a diet for Camponotus carpenter ants to facilitate experiments on nutritional requirements of these ants. Worker colonies of Camponotus floridanus were fed with a chemically defined diet, containing all essential minerals, amino acids, vitamins, growth factors and sucrose in an agar matrix. After 13 weeks, neither the number of raised pupae, their dry weight, nor the mortality of workers in subcolonies fed with this diet differed significantly from control colonies fed with Bhatkar-Whitcomb-agar, in addition to cockroaches and diluted honey. Therefore, this diet is adequate for a normal brood production and a maximal growth rate of C. floridanus larvae, at least for a period of three months. This diet should be suitable for ants that are able to feed on agar-based food resources in general. Received 6 September 2006; revised 5 October 2006; accepted 18 October 2006. An erratum to this article is available at .     

Selection for tonic immobility duration does not affect the response to novelty in quail

Genetic selection on a single fear test, the tonic immobility test, seems to result in selection on fearfulness, i.e. the propensity to exhibit fear responses, whatever the fear tests used. However, the conception of fear as a single variable has been challenged by the recognition that fear is multidimensional. This study was designed to test whether genetic selection on a classic index of fear in birds, tonic immobility duration, is accompanied by changes in the response to a single dimension of fear – novelty.Two lines of quail divergently selected for long (LTI) or short (STI) duration of tonic immobility were exposed to a novel object in their home cage. Quail of both lines showed typical fear reactions in response to novelty but there was no difference between lines. We conclude that genetic selection for tonic immobility duration does not affect all dimensions of fear, notably not novelty. Further studies are needed to investigate the dimensions of fear on which the two lines of quail could have been selected.     

A new ethological test to study nestmate recognition in adult ants

Summary An ethological test was designed to investigate nestmate recognition in adult ants. Contrary to classic dyadic tests, it consisted of a choice situation where a tested-worker was faced with nestmate and non-nestmate workers. These were kept alive, tied down, and thus immobilised in the neutral arena to record the tested-worker's reactions independently of the behaviour of the others. Such tests, applied to the ponerine ant,Ectatomma tuberculatum, enabled us to record various measures of discrimination and to limit aggressive behaviours between alien ants, which often leads to serious injury in dyadic tests. They also demonstrated the influence of age on discrimination behaviour in this species.     

Hibernation does not affect memory retention in bats

Long-term memory can be critically important for animals in a variety of contexts, and yet the extreme reduction in body temperature in hibernating animals alters neurochemistry and may therefore impair brain function. Behavioural studies on memory impairment associated with hibernation have been almost exclusively conducted on ground squirrels (Rodentia) and provide conflicting results, including clear evidence for memory loss. Here, we for the first time tested memory retention after hibernation for a vertebrate outside rodents—bats (Chiroptera). In the light of the high mobility, ecology and long life of bats, we hypothesized that maintenance of consolidated memory through hibernation is under strong natural selection. We trained bats to find food in one out of three maze arms. After training, the pre-hibernation performance of all individuals was at 100 per cent correct decisions. After this pre-test, one group of bats was kept, with two interruptions, at 7°C for two months, while the other group was kept under conditions that prevented them from going into hibernation. The hibernated bats performed at the same high level as before hibernation and as the non-hibernated controls. Our data suggest that bats benefit from an as yet unknown neuroprotective mechanism to prevent memory loss in the cold brain.     

Density-dependent natural selection does not increase efficiency

Summary Populations ofDrosophila melanogaster kept at high population density (K-selected) for 125 generations have higher larval viability than populations kept at low densities (r-selected) when both are raised under crowded conditions. In additionK-selected adults that emerge from crowded cultures are larger than theirr-selected counterparts. These differences cannot be explained by differences in efficiency of food use. The minimum food required for successful pupation is actually greater in theK-selected populations. I conjecture that there may be a trade-off between minimum food requirements and competitive ability, which has changed substantially in theK-selected populations. The possibility thatK-selected larvae can dig more more deeply and gain access to unused food is examined and rejected as a possible explanation of the viability differences. Evidence is provided supporting the hypothesis that the differences in viability may be due to an increased tendency of theK-selected larvae to pupate off the surface of the medium.     

Pretreatment with heat does not affect double-strand breaks DNA rejoining in Chlamydomonas reinhardtii

We aimed to clarify if heat pretreatment could protect Chlamydomonas reinhardtii cells from gamma rays DNA damaging action. It was studied whether: (1) heat pretreatment could accelerate DNA DSB rejoining; (2) chloroplast chaperones (HSP70B, HSP90C) could be involved in protection from radiation-induced DNA DSB.It was obtained that heat pretreatment (37–42 °C) induced minor DNA DSB levels which might be insufficient as signals for DNA DSB repair induction. No correlation between chaperones overproduction and DNA DSB rejoining was shown. These are probably the first data that HSP70B and HSP90C do not protect DNA against radiation-induced damage in a plant model system.     

Bioassay design and length of time in the laboratory affect intercolonial interactions of the Formosan subterranean termite (Isoptera, Rhinotermitidae)

This study examined the effect of diet, experimental design, and length of time in the laboratory on intercolonial agonism among Formosan subterranean termite, Coptotermes formosanus Shiraki, colonies. In pairings of 12 C. formosanus Shiraki colonies collected in an urban forest, there was no significant reduction in survival of termites in 30 out of 59 colony pairs compared to colony controls, but there was <50% survival in 18 colony pairs and <10% survival in six colony pairs. There was no correlation between the level of aggressive behavior and the laboratory diet of the termites. Effect of bioassay design and length of time in the laboratory was evaluated in three colony pairs where tests were first conducted on the day of field collection, then colony pairs were retested every 7 days. Aggressive behavior decreased over time in both bioassays, but it tended to decrease more rapidly in the Petri dish tests. The rapid loss of agonism in groups of termites kept in the laboratory demonstrates that changes in environmental factors affect intercolonial agonism. This article presents the results of research only. Mention of a commercial or proprietary product does not constitute endorsement or recommendation by the USDA.     

Species-specific effects of tending ants on the development of lycaenid butterfly larvae

The transfer of nutrients between organisms is a common feature of mutualism. The production of these food rewards is often assumed to be costly. Estimation of the costs of producing food rewards is important for understanding the overall effects of the interaction on fitness. When food rewards are harvested by several species differing in foraging behavior, costs to the producer may differ. The larvae of many species in the butterfly family Lycaenidae produce secretions consumed by tending ants. Here I report that three North American ant species, Formica perpilosa, Dorymyrmex sp. (smithi complex), and Forelius foetida, had no negative effect on the duration of development and adult size of the lycaenid Hemiargus isola. Moreover, tending by the ant Formica perpilosa significantly enhanced larval growth, resulting in butterflies that were 20% heavier than their untended counterparts. Tending by the ants Dorymyrmex sp. (smithi complex) and Forelius foetida had no effect on butterfly weight. Tended, nonfeeding larvae lost 69% more weight than untended, nonfeeding larvae. Taken together, the results suggest that, although ant tending imposes a physiological cost, H. isola larvae use behavioral or physiological mechanisms to compensate or overcompensate for nutrients lost to ants.     

Preharvest application of exogenous abscisic acid (ABA) or an ABA analogue does not affect endogenous ABA concentration of onion bulbs

Bulb abscisic acid (ABA) concentration has been shown to decrease in stored onions, and onset of sprouting to occur at minimal ABA concentration. It was postulated that increasing prestorage bulb ABA concentration could increase storage life. Analogues of ABA that enhance biological activity and resist degradation are available and are becoming commercially viable. Exogenous ABA and an ABA analogue (8′-methylene ABA methyl ester; PBI-365) were applied separately as preharvest foliar sprays to six onion cultivars with varying storage potential. Quality indicators including pyruvate, total soluble solids and firmness were determined at regular intervals during storage. Neither ABA treatment increased endogenous bulb ABA concentration. Bulb ABA concentration decreased during storage and the onset of sprouting occurred at a minimal ABA concentration (ca. 50–120 ng g⁻¹ DW). This was followed by an increase in ABA concentration as sprout growth continued. No straightforward relationship between ABA and carbohydrate metabolism could be determined.     

Melatonin does not affect the black pigment migration in the crab Neohelice granulata

N-acetyl-5-methoxytryptamine or melatonin is a multifunctional molecule. The main physiological function, at least in vertebrates, is to transduce to the animal the photoperiodic information and regulate rhythmic parameters. But studies have also observed the action of this molecule on pigment migration in ectothermic vertebrates. Thus the aim of this paper was to investigate in vivo and in vitro the influence of melatonin on the pigment migration in melanophores of the crab Neohelice granulate. Injections of melatonin (2 × 10⁻⁹ moles · crab⁻¹) at 07:00 h or 19:00 h did not affect (p > 0.05) the circadian pigment migration of the melanophores in constant darkness. Additionally no significant pigment migration (p > 0.05) was verified in normal and eyestalkless crabs injected with melatonin (10⁻¹⁰–10⁻⁷ moles · crab⁻¹) during the day or night. In the ^{in vitro} assay, the response of melanophores to the pigment-dispersing hormone in eyestalkless crabs injected with melatonin (2 × 10⁻⁹ moles · crab⁻¹) 1 and 12 hours before the observations did not differ (p > 0.05) from the control group (injected with physiological solution). These results suggest that melatonin does not act as a signaling factor for pigment dispersion or aggregation in the melanophores of N. Granulate.     

Effects of the concurrent exclusion of ants and earwigs on aphid abundance in an organic citrus grove

Based on the well-known mutualism between ants (Hymenoptera: Formicidae) and aphids (Homoptera: Aphididae), we conducted a five-year experiment of ant-exclusion from the canopies of citrus trees as a possible method of biological control of aphids. However, our results showed that the exclusion of ants from the canopies increased, instead of reducing, aphid abundance. To explain this unexpected result, we reasoned that the exclusion of ants from the canopies might also have excluded crawling insects that prey on aphids, such as the European earwig (Forficula auricularia L., Dermaptera: Forficulidae). Such a possibility is supported by the negative relationship between aphid density and the abundance of earwigs, consistent with a top-down control of aphids by earwigs. In contrast, the abundance of other aphid predators (Coleoptera: Coccinellidae, and Heteroptera) had no such negative effect on aphid density but a positive one, suggesting a bottom-up control, and showed no differences between control and ant-excluded trees. Thus, the most likely explanation for the increase in aphid abundance in the ant-excluded trees is the absence of earwigs from the canopies of the experimental trees, providing further evidence of the major role that earwigs play as control agents of aphids in cultivated trees.     

Doronomyrmex pocahontas: not a workerless parasite but still an enigmatic taxon (Hymenoptera,Formicidae)

Summary New data suggest that the North American antDoronomyrmex pocahontas Buschinger 1979, originally described as a workerless inquiline, is not a social parasite. Breeding experiments show a remarkable phenotypic plasticity, which is probably due to hybridization or to intraspecific polymorphism.