The influence of ants on patterns of colonization and establishment within a set of coexisting lycaenid butterflies in a south-east Asian tropical rain forest

In Peninsular Malaysia ten species of lycaenid butterflies use leaf flushes or inflorescences of the legume tree Saraca thaipingensis as larval hostplant. Resource partitioning among these species is regulated by a complex mixture of patterns of interaction with ants. Females of obligately myrmecophilous species lay their eggs exclusively on trees colonized by their specific host ants. On trees colonized by weaver ants, only specialist mutualists adapted to these territorial ants are able to survive, while larvae of other species are killed. The formicine ant Cladomyrma petalae, which inhabits hollow twigs of the myrmecophytic hostplant, likewise precludes oviposition by female butterflies. Lycaenid larvae confronted with this ant species never survive, but one concealed feeding species (Jamides caeruleus) escapes removal due to the cryptic life-habits of the larvae. Two facultative myrmecophiles associate in a mutualistic way with a wide and largely overlapping range of ant genera which forage at the extrafloral nectaries of leaf flushes. One species (Cheritra freja) is not myrmecophilous, but is tolerated by all but the most territorial ants. Ant-dependent hostplant selection and egg-clustering characterize the obligate mutualists, whereas facultative myrmecophiles and the non-myrmecophile distribute their eggs singly over appropriate hostplants. Signals mediating caterpillar-ant communication are highly specialized in one obligate myrmecophile (Drupadia theda), but rather unspecific in four other species tested. Altogether our observations indicate that colonization and establishment of lycaenid butterflies on S. thaipingensis trees are governed by specializations as well as opportunistic use of resources (ants and hostplant parts). Therefore, the diversity of this species assemblage is maintained by deterministic as well as stochastic factors.     

Connectivity compensates for low habitat quality and small patch size in the butterfly <Emphasis Type="Italic">Cupido minimus</Emphasis>

Habitat size, habitat isolation and habitat quality are regarded as the main determinants of butterfly occurrence in fragmented landscapes. To analyze the relationship between the occurrence of the butterfly Cupido minimus and these factors, patch occupancy of the immature stages in patches of its host plant Anthyllis vulneraria was studied in the nature reserve Hohe Wann in Bavaria (Germany). In 2001 and 2002, 82 A. vulneraria patches were surveyed for the presence of C. minimus larvae. The occurrence was largely affected by the size of the food plant patches. In a habitat model that uses multiple logistic regression, the type of management and habitat connectivity are further determinants of species distribution. Internal and temporal validation demonstrate the stability and robustness of the developed habitat models. Additionally, it was proved that the colonization rate of C. minimus was significantly influenced by the distance to the next occupied Anthyllis patch. Concerning long-term survival of (meta-) populations in fragmented landscapes, the results show that lower habitat quality may be compensated by higher connectivity between host plant patches. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genotype-environment interactions for insect growth in constant and fluctuating temperature regimes

Experiments on life history genetics are usually performed using constant temperature environments in the laboratory. However, the dynamics of insect growth can be influenced profoundly by daily fluctuations in temperature such as those which characterize field environments. We report here on experiments using different stocks and selected lines of a tropical butterfly, Bicyclus anynana, to examine whether genotype-environment interactions occur for three traits describing pre-adult growth. These traits were measured over two pairs of environments differing in mean temperature, each of which had a constant, and a cycling temperature regime. Development time, pupal weight and growth rate show genotype-environment interactions, especially at comparatively low average temperatures. Researchers should, therefore, take care when extrapolating from the form of genetic covariance matrices and ''trade-offs'' among life history traits found in constant temperature environments to those likely to occur in nature. <br>     

On the failure of two butterfly species to respond to the presence of conspecific eggs prior to oviposition

Abstract. 1. The eggs of Euptychiine butterflies are laid singly, but their distributions tend to be contagious. However, these insects do not discriminate between egg-laden and egg-free plants.
2. Response to conspecific eggs is not part of the mechanism responsible for clumped egg distribution.     

Exotic grass invasion impacts fitness of an endangered prairie butterfly, <Emphasis Type="Italic">Icaricia icarioides fenderi</Emphasis>

Fender’s blue butterfly is an endangered species restricted to fragmented, grassland remnants that are becoming increasingly dominated by tall, invasive grasses in western Oregon, USA. I performed a removal experiment to assess the impacts of structural degradation accompanying the invasion of Arrhenatherum elatius, tall oat grass, on butterfly fitness and fitness related behaviors. Clipping of A. elatius to native grass sward height resulted in 2.5–5 times as many eggs laid per leaf of host plant. Both male and female butterflies basked more frequently in areas removed of A. elatius inflorescences and upon encountering the treatment edge butterflies had a high rate of return into a large area removed of the grass inflorescences. Although butterfly behavior appeared to be affected by the change in sward height on the treatment edge, there was no evidence for the edge causing a disproportionate egg load. Invasion and dominance by A. elatius appeared to diminish host plant apparency which may result in overloading of eggs on conspicuous host plants, increased incidence of emigration, and a decrease in the likelihood of colonization because female butterflies appeared indifferent to larval resources beneath A. elatius inflorescences. Dominance of natural shortgrass prairies by tall stature grasses like A. elatius may be an insidious form of habitat degradation for grassland Lepidoptera worldwide, but it may go largely unnoticed because larval and adult resources can persist under the unnaturally tall grass canopy.     

PARALLEL RACE FORMATION AND THE EVOLUTION OF MIMICRY IN HELICONIUS BUTTERFLIES: A PHYLOGENETIC HYPOTHESIS FROM MITOCHONDRIAL DNA SEQUENCES

Mimicry has been a fundamental focus of research since the birth of evolutionary biology yet rarely has been studied from a phylogenetic perspective beyond the simple recognition that mimics are not similar due to common descent. The difficulty of finding characters to discern relationships among closely related and convergent taxa has challenged systematists for more than a century. The phenotypic diversity of wing pattens among mimetic Heliconius adds an additional twist to the problem, because single species contain more than a dozen radically different-looking geographical races even though the mimetic advantage is theoretically highest when all individuals within and between species appear the same. Mitochondrial DNA (mtDNA) offers an independent way to address these issues. In this study, Cytochrome Oxidase I and II sequences from multiple, parallel races of Heliconius erato and Heliconius melpomene are examined, to estimate intraspecific phylogeny and gauge sequence divergence and ages of clades among races within each species. Although phenotypes of sympatric races exhibit remarkable concordance between the two species, the mitochondrial cladograms show that the species have not shared a common evolutionary history. H. erato exhibits a basal split between trans- and cis-Andean groups of races, whereas H. melpomene originates in the Guiana Shield. Diverse races in either species appear to have evolved within the last 200,000 yr, and convergent phenotypes have evolved independently within as well as between species. These results contradict prior theories of the evolution of mimicry based on analysis of wing-pattern genetics.     

Ultrastructure and morphogenesis of the wing scales in Heliconius erato phyllis (Lepidoptera: Nymphalidae): What silvery/brownish surfaces can tell us about the development of color patterning?

Usually the literature on Heliconius show three types of scales, classified based on the correlation between color and ultrastructure: type I – white and yellow, type II – black, and type III – orange and red. The ultrastructure of the scales located at the silvery/brownish surfaces of males/females is for the first time described in this paper. Besides, we describe the ontogeny of pigmentation, the scale morphogenesis and the maturation timing of scales fated to different colors in Heliconius erato phyllis. The silvery/brownish surfaces showed ultrastructurally similar scales to the type I, II and III. The ontogeny of pigmentation follows the sequence red, black, silvery/brownish and yellow. The maturation of yellow-fated scales, however, occurred simultaneously with the red-fated scales, before the pigmentation becomes visible. In spite of the scales at the silvery/brownish surfaces being ultrastructurally similar to the yellow, red and black scales, they mature after them; this suggests that the maturation timing does not show a relationship with the scale ultrastructure, with the deposition timing of the yellow pigment. The analysis of H. erato phyllis scale morphogenesis, as well as the scales ultrastructure and maturation timing, provided new findings into the developmental architecture of color pattern in Heliconius.     

Thermal biology of flight in a butterfly: genotype,flight metabolism,and environmental conditions

Knowledge of the effects of thermal conditions on animal movement and dispersal is necessary for a mechanistic understanding of the consequences of climate change and habitat fragmentation. In particular, the flight of ectothermic insects such as small butterflies is greatly influenced by ambient temperature. Here, variation in body temperature during flight is investigated in an ecological model species, the Glanville fritillary butterfly (Melitaea cinxia). Attention is paid on the effects of flight metabolism, genotypes at candidate loci, and environmental conditions. Measurements were made under a natural range of conditions using infrared thermal imaging. Heating of flight muscles by flight metabolism has been presumed to be negligible in small butterflies. However, the results demonstrate that Glanville fritillary males with high flight metabolic rate maintain elevated body temperature better during flight than males with a low rate of flight metabolism. This effect is likely to have a significant influence on the dispersal performance and fitness of butterflies and demonstrates the possible importance of intraspecific physiological variation on dispersal in other similar ectothermic insects. The results also suggest that individuals having an advantage in low ambient temperatures can be susceptible to overheating at high temperatures. Further, tolerance of high temperatures may be important for flight performance, as indicated by an association of heat‐shock protein (Hsp70) genotype with flight metabolic rate and body temperature at takeoff. The dynamics of body temperature at flight and factors affecting it also differed significantly between female and male butterflies, indicating that thermal dynamics are governed by different mechanisms in the two sexes. This study contributes to knowledge about factors affecting intraspecific variation in dispersal‐related thermal performance in butterflies and other insects. Such information is needed for predictive models of the evolution of dispersal in the face of habitat fragmentation and climate change.     

中国爻蛱蝶属与耳蛱蝶属(鳞翅目,蛱蝶科)分类地位探讨

通过对耳蛱蝶Eulaceura osteria与爻蛱蝶Herona marathus的成虫形态特征、雌雄外生殖器解剖特征、地理分布的比较研究,并结合闪蛱蝶亚科系统发育分析结果,表明耳蛱蝶与爻蛱蝶成虫外部形态特征及雌雄外生殖器解剖特征存在许多相同之处,地理分布相互重叠;系统发育分析结果该2种并入同一支系,互为姊妹群关系;建议将耳蛱蝶归入爻蛱蝶属中,同时将耳蛱蝶属作为爻蛱蝶属的异名处理。     

Are gardens effective in butterfly conservation? A case study with the pipevine swallowtail, <Emphasis Type="Italic">Battus philenor</Emphasis>

Gardens with nectar sources and larval host plants have been proposed to stem the decline in butterfly abundance caused by habitat loss. However, no study has provided evidence that gardens benefit butterflies. We examined the use of natural sites and gardens in the San Francisco bay area by the butterfly, Battus philenor. We found that natural sites were more likely to attract adult B. philenor, received more oviposition, and had higher juvenile survival than gardens sites. Butterflies were more likely to be present in gardens with established populations of the host plant, Aristolochia californica, growing in the sun. Battus philenor are unlikely to visit gardens with host plants planted within the past 7 years. Gardens between the ages of 8–40 years received oviposition, but did not always support completion of larval development of B. philenor. In gardens with host plants over 40 years of age, B. philenor consistently survived from egg to the adult stage. Natural enemy induced mortality of eggs did not differ between garden and natural sites, but overall egg survival was lower in gardens than at natural sites. It is unlikely that gardens serve as 'refugia' for B. philenor in years when populations in natural sites experience low survival or low fecundity. Even in gardens capable of supporting larvae to maturity, the density of eggs and survival rates were lower than in natural populations of the host plant suggesting that gardens were not optimal habitats. Therefore, without evidence that juvenile abundance and survival rates in gardens matches or exceeds that in natural sites, it is most likely that gardens act as population sinks for B. philenor.