Life history and host range of the leaf blotcher Eucosmophora schinusivora: a candidate for biological control of Schinus terebinthifolius in the USA

The host range of Eucosmophora schinusivora Davis and Wheeler (Lepidoptera: Gracillariidae) was studied to assess its suitability as a biological control agent of Schinus terebinthifolius Raddi (Anacardiaceae), a serious environmental and agricultural weed in the USA and elsewhere in the world. The life history of this insect species and its host range were determined in the laboratory with adult no-choice oviposition and larval development tests. This species has five instars, the first three are sap-feeding miners and the last two are tissue feeding. Total development time was 31.7 days. To examine specificity of this species, 10 plant species in Anacardiaceae were selected based on taxonomic relatedness to S. terebinthifolius, economic importance, and availability. In the laboratory, except for Anacardium occidentale and Cotinus obovatus, all of the tested species were accepted for oviposition with a marked preference for the weed S. terebinthifolius, Schinus molle, Rhus copallinum, Rhus sandwicensis and Pistacia chinensis. Complete development, from egg to adult, was achieved only on S. terebinthifolius, S. molle, R. copallinum, P. chinensis and Metopium toxiferum. In conclusion, E. schinusivora will not be considered for the biological control of S. terebinthifolius in the continental USA. However, the utilisation of this species in other infested areas such as Hawai'i and Australia should be considered.     

Towards a Revision of the Systematics of the Genus Chlamydomonas (Chlorophyta)

Strains of Chlamydomonas with cross-reacting sporangium wall autolysins also correspond in morphology, reproduction, development, and physiological properties. We therefore undertook a revision of the systematics of the genus based on this correlation. Isolates of Chlamydomonas available in culture collections were re-examined microscopically, preferably with respect to their reproduction and development. In particular all authentic clones, on which earlier species diagnoses had been founded, were included. Their detectable autolysins were tested crosswise in bioassays. We intend to complete and extend species diagnoses in order to separate species more precisely. - At first 7 strains with a common sporangium autolysin have been examined, four of which are the authentic cultures of the species C. aggregate Deason et Bold, C. akinetos Deason et Bold, C. applanata Pringsheim, and C. humicola Lucksch. They have been brought together under the name of the species first described, C. applanata Pringsheim, due to their apparent similarities in morphology and development. An amended species diagnosis is presented. The significance of authentic cultures as important sources of further information is discussed.     

Interspecific competition between the braconid endoparasitoids Glyptapanteles porthetriae and Glyptapanteles liparidis in Lymantria dispar larvae

The effect of interspecific competition between the solitary endoparasitoid Glyptapanteles porthetriae Muesebeck (Hymenoptera: Braconidae) and the gregarious Glyptapanteles liparidis Bouché (Hymenoptera: Braconidae), was investigated in larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae). Host larvae were parasitized by both wasp species simultaneously in premolt to the 2^nd or the 3^rd host instar or in an additional approach with a 4‐day delay in parasitization by the second wasp species. Host acceptance experiments revealed that both wasp species do not discriminate between unparasitized host larvae and larvae parasitized previously by the same or the other species. In more than 90% female wasps parasitized the larva they encountered first. During the period of endoparasitic development, larvae of the competing parasitoid species never attacked the egg stage of the other species. When host larvae were parasitized simultaneously by both wasp species, the rate of successful development of both species depended on the age of the host larva at the time of its parasitization; G. liparidis emerged successfully from 44% of host larvae parasitized during the premolt to 2^nd instar, G. porthetriae from 28%, and in 20% of the hosts both parasitoid species were able to develop in one gypsy moth larva. However, when host larvae were parasitized simultaneously during premolt to the 3^rd instar, G. liparidis was successful in 90% of the hosts, compared to 8% from which only G. porthetriae emerged. In the experiments with delayed oviposition, generally the species that oviposited first succeeded in completing its larval development. Larvae of the species ovipositing with four days delay were frequently attacked and killed by larvae of the first parasitizing species or suffered reduced growth. As the secondary parasitoid species, G. porthetriae‐larvae were never able to complete their development, whereas G. liparidis developed successfully in at least 12,5% of the multiparasitized host larvae. Thus, multiparasitism of gypsy moth larvae by both Glyptapanteles species corresponds to the contest type; however, G. porthetriae is only able to develop successfully as the primary parasitoid of young host larvae.     

Testing the invulnerability of laboratory island communities to invasion

Summary One hundred communities were developed through the controlled introductions of microorganisms to beakers over a six month period of time. Following three months of development, a series of three separate previously unencountered species were introduced into each community. The persistences of these invaders were monitored and their relationships to invaded community complexity, composition and history of development evaluated. The null hypothesis that colonization success is independent of community complexity cannot be rejected. The rate at which species were introduced during development of these communities, as well as beaker size, influenced the invasion success of Dictyosphaerium, but not Staurastrum or Platydorina. The assembled communities were of two types: those dominated by Ochromonas and those domnated by Paramecium bursaria. Ochromonas dominated communities were invulnerable to the invasion of the above 3 species; no clear pattern of invulnerability was evident for P. bursaria communities.     

The ecology of mosquito larvae (Diptera: Culicidae) in the subalpine zone of the eastern Sierra Nevada Mountains,California, U.S.A.

Mosquito larvae were collected from the subalpine region of the eastern Sierra Nevada Mountains from 2011 to 2014. Two watersheds were sampled and sites selected were mainly vernal snow‐melt pools and wet meadows. Seven Aedes species, Culiseta incidens (Thomson), and Culex tarsalis Coquillett were collected. The most abundant and widely distributed species were Ae. hexodontus Dyar and Ae. tahoensis Dyar. Aedes tahoensis was the predominate species in woodland snow‐melt habitats. Some species were found at most elevations while others were found more often at specific elevations. The most restrictive species was Ae. ventrovittis Dyar which occurred almost exclusively between 3,219 m a.s.l. and 3,390 m a.s.l. Shannon and Simpson species diversity indices demonstrated that species diversity was greater in meadow habitats compared to woodland habitats. Mixed woodland/meadows, rock pools, and shallow grass pools were intermediate in species diversity. Abiotic factors such as snowpack and water temperature impacted species development times and when habitats dried. It was concluded that spatial and temporal patterns of habitats, along with elevation, influenced species presence and larval development. The results of the present study and previous work in the eastern Sierras will help guide future research that focuses on the potential change in the distribution and seasonality of subalpine mosquitoes and disease potential in the eastern Sierras as climatic conditions change.     

Conservation, innovation, and the evolution of horned beetle diversity

Beetle horns represent an evolutionary novelty exhibiting remarkable diversity above and below the species level. Here, we show that four typical appendage patterning genes, extradenticle (exd), homothorax (hth), dachshund (dac), and Distal-less (Dll) are expressed in the context of the development of sexually dimorphic thoracic horns in three Onthophagus species. At least two of these genes, Dll and hth, exhibited expression patterns consistent with a conservation of patterning function during horn development relative to their known roles in the development of insect legs. exd, hth, and dac expression patterns during horn development were largely invariable across species or sexes within species. In contrast, Dll expression was far more discrete and exhibited consistent differences between sexes and species. Most importantly, differences in location and domain size of Dll expression tightly correlated with the degree to which prepupal horn primordia were retained or resorbed before the final adult molt. Our results lend further support to the hypothesis that the origin of beetle horns relied, at least in part, on the redeployment of already existing developmental mechanisms, such as appendage patterning processes and that changes in the exact location and domain size of Dll expression may represent important modifier mechanisms that modulate horn expression in different species or sexes. If correct, this would imply that certain components of genetic basis of horn development may be able to diversify rapidly within lineages and largely independent of phylogenetic distance. We present a first model that integrates presently available data on the genetic regulation of horn development and diversity.     

Temperature‐dependent development of the parasitoid Tachinaephagus zealandicus on five forensically important carrion fly species

The influences of temperature and host species on the development of the forensically important parasitoid Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) were studied at six constant temperatures in the range of 15–30°C. T. zealandicus completed development successfully between 15°C and 27°C on five species of Calliphoridae, Calliphora albifrontalis Malloch, Calliphora dubia Macquart, Lucilia sericata Meigen, Chrysomya rufifacies Macquart and Chrysomya megacephala Fabricius. No adult parasitoids emerged from any of the host species reared at 30°C. Temperature and host species significantly influenced development time, emergence success and progeny size. Development was significantly longer on Ch. megacephala and Ch. rufifacies at 18–24°C and significantly longer on Ch. rufifacies and C. albifrontalis at 15°C and 27°C. Parasitoid emergence success was greatest at 21°C, declined at the temperature extremes (15°C and 27°C) and was significantly lower on Ch. megacephala and Ch. rufifacies than on the three other host species. Progeny numbers per host pupa were highest at 21–24°C, declined on either side of this temperature range and were significantly lower on L. sericata, Ch. rufifacies and Ch. megacephala than on either C. dubia or C. albifrontalis. An effect of host species on sex ratio was only observed at 27°C, at which a higher proportion of T. zealandicus females emerged from Ch. megacephala and Ch. rufifacies than from the other host species. The thermal requirements for development (developmental thresholds, thermal constant, optimum temperature) of T. zealandicus in each host species were estimated using linear and non‐linear models. Upper and lower developmental thresholds ranged between 29.90°C and 31.73°C, and 9.73°C and 10.08°C, respectively. The optimum temperature for development was estimated at between 25.81°C and 27.05°C. Given the significant effect of host species on development time, the use of parasitoid–host‐specific developmental data in forensic application is recommended.     

The effect of temperature on the development times of eggs,naupliar and copepodite stages of five species of cyclopoid copepods

The duration times of eggs, combined naupliar instars and of the different copepodite stages of five species of cyclopoid copepods — Acanthocyclops robustus, Cyclops vicinus, Diacyclops bicuspidatus, Mesocyclops leuckarti, and Thermocyclops crassus — were investigated at five different temperatures. The five species can be divided in two groups: two species, C. vicinus and D. bicuspidatus, adapted to cold water conditions and three species, A. robustus, M. leuckarti and T. crassus adapted to warm water conditions. The cold water species showed a faster egg development than M. leuckarti and T. crassus at 5–15 °C. The eggs and instars of the warm water species M. leuckarti tend to develop faster than those of the former two species at higher temperatures. A. robustus showed the shortest egg and instar development at 10–25 °C. The warm water species T. crassus produced no eggs at 10 °C and temperatures below. At higher temperatures (20, 25 °C) the egg and instar duration times were similar or longer than those of the other species. When cultured in total darkness a great part of the C_IV respectively C_V copepodites of the summer forms entered arrest and the percentage of copepodites that showed an arrest of development was highest at lowest temperatures. The present results are compared with data from literature and differences are discussed.     

Comparative neuromorphology of the telencephalon of sturgeon of the genera Acipenser, Huso and Scaphirhynchus (Actinopterygii; Acipenseridae)

Brain anatomy and structure, composition of the neurons, and cytoarchitectural maps were compared between five species of Acipenser, one species of Huso and two species of Scaphirhynchus. Morphological differences in the forebrain structure between species and genera were apparent. The evolutionary history of the Acipenseridae has been marked by an extensive mosaic radiation in the evolutionary development of the inner structure of their brains. Members of Scaphirhynchus have a very simple telencephalon structure differing significantly from that of Huso and Acipenser. It is clear that neuromorphological variation of sturgeon species will serve as an additional data useful in understanding the evolutionary processes and history associated with the speciation in Acipenseridae.     

Preference and performance of the sawfly Diprion pini on host and non-host plants of the genus Pinus

The sawfly, Diprion pini L., is a pest of Pinus in Europe and is mainly found on P. sylvestris L. and P. nigra laricio Poiret. The relative importance of female oviposition capacity and behaviour, egg development, and larval survival on a new host plant was measured on 11 pine species. Five were natural host plants and six non-host plants, five of which are not indigenous to Europe. Oviposition choice tests showed that females discriminated between the pine species. Egg and larval development also differed between pine species. However, the female choice was not linked with hatching rate and larval development. Results of biological tests clearly indicated that there were different response patterns of D. pini life stages in relation to pine species, and these patterns were the same with insects of four different origins. We discuss the importance of each potential barrier to colonisation of a new host.     

Establishment and Growth of Living Fence Species: An Overlooked Tool for the Restoration of Degraded Areas in the Tropics

Numerous tree species can establish by vegetative means in the tropics. Many are used in agriculture as living fences and in alley cropping and could also be used in a restorational setting. However, little is known about their establishment ability. This study evaluated the establishment ability and cover development of multiple species in three separate field trials in northern Honduras. First, 11 species were evaluated for their ability to establish in a common garden experiment. Second, of the former species, Bursera simaruba and Gliricidia sepium were evaluated for 2 years for their ability to establish vegetatively and develop cover at three deforested sites. Lastly, a study examined whether greater initial stake height and diameter at breast height increased the establishment success and crown development of G. sepium stakes. First, five species, Erythrina berteroana, Erythrina fusca, Jatropha curcas, G. sepium, and B. simaruba, had high establishment success. Others showed promise but may have been planted in the wrong season. Second, establishment for G. sepium was nearly 100% at all sites, whereas B. simaruba ranged from 30–50%. Gliricidia sepium stakes developed more rapidly and attained greater cover than B. simaruba. Dry season planting may increase the establishment success of both species. Lastly, greater initial stake height and diameter at breast height each resulted in greater crown development for G. sepium. The use of living fence species as a restorational tool has been overlooked. Aside from the advantages of planting tree species vegetatively, species can act as seed recruitment foci by attracting seed dispersers and provide shade to improve microclimatic conditions for seedling establishment. The technique described is simple and could have broad application throughout tropical regions.     

Interspecific competition between the braconid endoparasitoids Glyptapanteles porthetriae and Glyptapanteles liparidis in Lymantria dispar larvae

The effect of interspecific competition between the solitary endoparasitoid Glyptapanteles porthetriae Muesebeck (Hymenoptera: Braconidae) and the gregarious Glyptapanteles liparidis Bouché (Hymenoptera: Braconidae), was investigated in larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae). Host larvae were parasitized by both wasp species simultaneously in premolt to the 2^nd or the 3^rd host instar or in an additional approach with a 4-day delay in parasitization by the second wasp species. Host acceptance experiments revealed that both wasp species do not discriminate between unparasitized host larvae and larvae parasitized previously by the same or the other species. In more than 90% female wasps parasitized the larva they encountered first. During the period of endoparasitic development, larvae of the competing parasitoid species never attacked the egg stage of the other species. When host larvae were parasitized simultaneously by both wasp species, the rate of successful development of both species depended on the age of the host larva at the time of its parasitization; G. liparidis emerged successfully from 44% of host larvae parasitized during the premolt to 2^nd instar, G. porthetriae from 28%, and in 20% of the hosts both parasitoid species were able to develop in one gypsy moth larva. However, when host larvae were parasitized simultaneously during premolt to the 3^rd instar, G. liparidis was successful in 90% of the hosts, compared to 8% from which only G. porthetriae emerged. In the experiments with delayed oviposition, generally the species that oviposited first succeeded in completing its larval development. Larvae of the species ovipositing with four days delay were frequently attacked and killed by larvae of the first parasitizing species or suffered reduced growth. As the secondary parasitoid species, G. porthetriae-larvae were never able to complete their development, whereas G. liparidis developed successfully in at least 12,5% of the multiparasitized host larvae. Thus, multiparasitism of gypsy moth larvae by both Glyptapanteles species corresponds to the contest type; however, G. porthetriae is only able to develop successfully as the primary parasitoid of young host larvae.     

桑黄孔菌属的研究进展

历来"桑黄"的种类混淆不清,直至近年来才被确定为桑树桑黄,与其亲缘性相近的物种也一同被划分入广义纤孔菌属的新分支—桑黄孔菌属。本文整理曾被当作"桑黄"的物种,阐述其正名和桑黄孔菌属确立的过程,对目前该属内物种的生物活性和栽培研究进展进行综述,旨在为桑黄孔菌属真菌资源的研究开发提供参考。     

Reproductive biology of three sponge species of the genus Xestospongia (Porifera: Demospongiae: Petrosida) from the Great Barrier Reef

The reproductive development of three species of the Petrosida, Xestospongia bergquistia, X. exigua, and X. testudinaria, was monitored for four years on a fringing reef at Orpheus Island, Great Barrier Reef, Australia. All three species were oviparous and female reproductive activity began prior to males becoming active. X. bergquistia and X. testudinaria were gonochoric and broadcast eggs in spawning events that were synchronous within species. Egg development occurred over more than five months in X. bergquistia and X. testudinaria and two months in X. exigua. Spawning was during periods of warm temperature and occurred in October or November for X. bergquistia and X. testudinaria, and January or February for X. exigua. Lunar phase was implicated in timing of spawning of X. testudinaria. Diel timing of spawning in X. testudinaria and X. bergquistia was consistently a morning event.     

The impact of host plant species on the larval development of the large pine weevil Hylobius abietis L.

• 1 The developmental performance of the large pine weevil Hylobius abietis was studied in the laboratory on four species of conifer, Corsican pine Pinus nigra var. maritima, Sitka spruce Picea sitchensis, Douglas‐fir Pseudotsuga menziesii and Japanese larch Larix kaempferi.
• 2 All species supported development, but, there was considerable variation in larval mortality, development time and weight of adults on emergence between host species.
• 3 Levels of mortality were highest in Japanese larch (77%) and lowest in Corsican pine (8.2%), and the heaviest adults emerged from Corsican pine (130 mg) and the smallest from Douglas‐fir (74 mg).
• 4 A constitutive plant defence chemical, lignin, found to vary within a northern provenance of Sitka spruce, also strongly affected larval development.
• 5 The significance of these findings is discussed in relation to the management of H. abietis.

     

浙江省红楠生境地群落数量分类和环境解析

为探讨群落结构与环境因子对红楠Machilus thunbergii在浙江省分布及发展的影响,采用双向指示种分类(TWINSPAN)、典范对应分析(CCA)并结合种间联结分析,对浙江省172个红楠生境地群落进行数量分类排序与环境解析。结果表明:(1)TWINSPAN将172个样地群落分成8个群落类型,红楠在群落中为优势种或主要伴生种。群落类型的不同是影响红楠生长及更新的重要原因。(2)海拔高度及坡度是决定红楠分布及发展的主导环境因子。红楠作为优势种的生境地主要特征为海拔900m以下、坡度35°以下。(3)甜槠(Castanopsis eyrei)、青冈(Cyclobalanopsis glauca)、木荷(Schima superba)为群落中的稳定优势种,种间联结结果显示与红楠均为显著正关联。     

Interspecific and intraspecific variation of the duration and thermal requirements for egg development in carabid beetles (Coleoptera,Carabidae) in the North-West of Russia

The thermal norms of egg development were studied in the ground beetles Amara communis, A. nitida, Carabus granulatus, Platynus assimilis, Poecilus versicolor, Pterostichus oblongopunctatus (spring breeding species), P. melanarius, and P. niger (autumn breeding species). The adults were collected in soil traps near Arkhangelsk, St. Petersburg, Moscow, and Bryansk in May–June. Females and males were kept in pairs at 20°C and 22 h light per day. The eggs laid by females were kept at constant temperatures (12, 14, 16, 18, 20, and 22 ± 0.1°C). The development time for each egg was determined accurate to 0.5 day. From the values of the individual development rate (a reciprocal of development time) at all the temperatures, the thermal constants for development were calculated: the coefficient of linear regression (CLR) of the development rate on temperature, the sum of degree-days, and the thermal threshold for development (TTD). The egg development time was found to vary significantly between the species, except for A. communis, A. nitida, and C. granulatus. The values of CLR (i.e., the slopes of the regression lines) and TTD varied rather distinctly between the species and populations that revealed differences in the thermal requirements for egg development. In the spring breeding species the mean egg development time was significantly shorter, and the CLR and TTD values were on average higher than those of the autumn breeding species. Intraspecific latitudinal variation of the development time and the thermal requirements for egg development was revealed. The eggs laid by beetles from the Arkhangelsk population developed faster than those of the same species from the southern populations at all experimental temperatures. These differences were not great but statistically significant. At the same time, the differences between the CLR and TTD values for the northern and southern populations of the same species were non-significant in most cases. Thus, the main ecophysiological adaptation of carabid beetles during their northward expansion was the shortening of development time within the entire range of favorable temperatures, while the CLR and TTD values only insignificantly changed.     

Development of the gregarious ectoparasitoid Nasonia vitripennis using five species of necrophagous flies as hosts and at various developmental temperatures

The utility of five species of necrophagous flies (Diptera) as pupal hosts for Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) was examined by comparing incidences of parasitism, fecundity, and several features of wasp development at three rearing temperatures. Species differences in host suitability were evident in all life history features examined, with the highest incidences of parasitism, largest clutches and adult body sizes, and shortest periods of development occurring when the sarcophagid Sarcophaga bullata Parker served as hosts, regardless of temperature in which the wasps developed. Puparia of the calliphorids Lucilia illustris Meigen, Phormia regina Meigen, and Protophormia terraenovae Robineau‐Desvoidy were also accepted as hosts by the female parasitoids, albeit not equally so, and each yielded large, female‐biased broods. By contrast, pupae of the calliphorid Chrysomya rufifacies (Macquart) were not well suited to serve as an oviposition site or support the development of N. vitripennis. When successful parasitism did occur on any host species, duration of parasitoid development increased, adult body sizes were truncated, male‐biased sex ratios were produced, and mortality from egg hatch to adult emergence elevated with increasing rearing temperature. Unlike with the four other fly species, C. rufifacies did not yield any adult parasitoids when the rearing temperature was 35 °C. The results argue that developmental data determined for this wasp derived from a single host species is not sufficient for applying to all scenarios in which wasp development is necessary to estimate a postmortem interval or periods of insect activity.     

Negative dietary effects of Colorado potato beetle eggs for the larvae of native and introduced ladybird beetles

Aphidophagous ladybird beetles (Coleoptera: Coccinellidae) are attracted to and feed heavily on aphids, but many species will also feed opportunistically on other prey that they encounter. In potatoes (Solanum tuberosum L.) in Washington State, USA, coccinellids feed on both green peach aphids (“GPA,” Myzus persicae Sulzer) and eggs of the Colorado potato beetle (“CPB,” Leptinotarsa decemlineata Say). The guild of aphidophagous ladybirds includes two native species, Hippodamia convergens Guérin-Méneville and Coccinella transversoguttata Brown. Recently, an introduced species, Coccinella septempunctata L., has invaded and apparently displaced its native congener. A second exotic, Harmonia axyridis Pallas, has colonized the area and is becoming more abundant. We compared larval development of each species on a monotypic diet of GPA, a monotypic diet of CPB eggs, or a mixed diet of both GPA and CPB eggs. Our goal was to answer two questions: (1) do larvae of the four ladybird species benefit from including CPB eggs in their diet and (2) do the four ladybird species differ in their ability to utilize CPB eggs as prey? No larva of any species completed development on a pure diet of CPB eggs, and survivorship was highest for all species when they fed on a pure diet of GPA. One native species, H. convergens, and one exotic species, H. axyridis, exhibited significantly lower survivorship on a mixed diet of both CPB eggs and GPA, compared to a pure GPA diet; H. axyridis also took longer to develop from egg to adult when both prey were provided. Survivorship of the two Coccinella spp. was not altered by the inclusion of CPB eggs with GPA, although CPB eggs lengthened the development time of C. transversoguttata. Adult size was not consistently affected by diet for any of the coccinellids. Overall, no ladybird species benefited from the inclusion of potato beetle eggs in its diet. The two Coccinella species responded similarly to the inclusion of CPB eggs, and so we would not expect any difference in the success of coccinellid larval development in potato fields following the replacement of C. transversoguttata by C. septempunctata. Hippodamia convergens and H. axyridis, the two species whose survivorship was depressed by combining CPB egg and aphid prey, were also the two species that consumed the greatest number of CPB eggs during successful larval development. A comparison of total egg consumption by each species cohort suggested that displacement of the other species by H. axyridis would not alter CPB biological control, because the higher per capita feeding rate by H. axyridis larvae compensated for individuals’ greater mortality risk on a diet including CPB eggs.     

Reproductive biology of viviparous and oviparous species of the leaf beetle genus Oreina

In five species of the genus Oreina Chevrolat (Coleoptera, Chrysomelidae) we compared the size of offspring, the fecundity of the females, the timing of offspring production and female investment over the season. Two of the species, O. elongata and O. luctuosa, laid eggs, while O. cacaliae, O. gloriosa and O. variabilis gave birth to larvae. Offspring size corrected for female size was similar in the two oviparous species and in the viviparous O. cacaliae. In the two other viviparous species the larvae were two to three times bigger in relation to the female. The greater size of the offspring was not traded off for lower fecundity in these latter two species, yet the production of bigger larvae was associated with a longer laying period and thereby a spreading of reproductive investment over the season. The prediction of life history theory that higher investment in individual offspring should be traded off for lower fecundity could not be confirmed. The investigation of egg and larval development showed that in one of the oviparous species, O. luctuosa, the length of the egg stage was more variable. This corroborates the view that in this species the eggs can be retained for varying times before being laid. Greater size at birth does not necessarily lead to shortened developmental times: the larval periods of O. cacaliae, O. elongata, O. gloriosa and O. variabilis were all comparable although the larvae of the first two species were relatively smaller when laid; only the small larvae of O. luctuosa needed significantly longer for their development. For all growth parameters examined the differences between species were larger than the differences between populations. A comparison of larval growth of the oligophagous species O. cacaliae on three plant genera showed that larval growth rate is influenced by the food plant. However, the plant on which the larvae grew worst is apparently not chosen for oviposition in the field. A comparison with a phylogeny of the species based on allozymes suggests that species with similar reproductive parameters are closely related, yet that viviparity evolved independently in O. cacaliae on one hand and O. variabilis and O. gloriosa on the other.