EVOLUTION OF ADULT MORPHOLOGY AND LIFE-HISTORY CHARACTERS IN CAVERNICOLOUS PTOMAPHAGUS BEETLES

Morphological and life-history characters were determined for a series of six increasingly cavernicolous species of eastern United States Ptomaphagus beetles. Contrary to expectations, dimensions of only some adult structural characters uniformly covary as an overall measure of evolutionary adaptation for cave life. Adult reproductive characters that show adaptation for cave life are loss of reproductive seasonality and production of fewer and larger eggs. Significant change in pre-imaginal life-cycle stages was not found. This is in contrast to cavernicolous bathysciine beetles of Europe which show remarkable adaptive trends in pre-imaginal stages, but larval adaptations are not strongly coevolved with adult cave-adaptive characters. This suggests that evolution of cave adaptation in adult endopterygote insects occurs before and independently from that in larvae.     

A study of trophic niche partitioning between larval populations of reproductively isolated whitefish (Coregonus sp.) ecotypes

The abundance, spatio-temporal distribution, and feeding of larvae were compared from two reproductively isolated dwarf and normal ecotypes of whitefish ( Coregonus sp.) to test the hypothesis that larval ecotypes should reduce competition by using different resources. Contrary to a priori expectations, trophic niche partitioning between larval populations was much less pronounced than previously reported for the adult stages of fish ecotypes, presumably due to the lack of competition acting at this stage, and related to non-limiting food resources. Because this study was conducted in a single year and a single lake, we cannot however, strictly rule out the possibility that resource-based competition and resulting niche partitioning may occur at the larval stage in these species complexes. Nevertheless, this suggests for the first time, that resource-based selection at the larval stage may be relatively unimportant compared to that occurring at older life-history stages in driving the divergence and the development of reproductive isolation in sympatric fish ecotypes.     

Genetic exchange between anchialine cave populations by means of larval dispersal: the case of a new gastropod species Neritilia cavernicola

Despite being limited to caves, many anchialine taxa have disjunct insular distributions, which raises questions about their origins and colonization history. This study deals with the new gastropod Neritilia cavernicola sp. n. (Neritopsina: Neritiliidae) from anchialine caves on two islands in the Philippines that are separated by the deep Bohol Strait and situated 200 km apart along the coastline of Cebu Island. Neritilia cavernicola is an obligate stygobiont and most closely resembles Neritilia littoralis , which lives in interstitial waters of the Nansei-shoto Islands, Japan. Its eggs and larval shells are identical to those of other Neritilia species, despite their different adult habitats. This suggests a marine planktotrophic phase (as occurs in amphidromous riverine species of Neritilia ), and consequent migration between islands via ocean currents. Here we present the first genetic structure for anchialine cave organisms; comparisons of 1276 bp sequences from mitochondrial cytochrome oxidase I show no evidence of genetic isolation between the islands. All individuals evidently are part of a panmictic population and the low vagility of adults and their seemingly isolated cave habitats do not limit gene flow in N. cavernicola . This migration model, based on marine larval dispersal, may be widely applicable to anchialine stygobites with insular distributions, as many such organisms (including shrimps, crabs and fishes) are phylogenetically allied to amphidromous species.     

Entomological and parasitological study on phlebotomine sandflies in central and northern Albania

An entomological survey was carried out in two districts of central (Kruje) and northern (Lezhe) Albania. Six collecting sites, showing a variety of diurnal resting sites, were monitored for adult sandflies from June through October 2002. Flies were collected with CDC miniature light traps, sticky traps and mechanical or hand aspirators in peridomestic sites, in bedrooms and inside cow barns, chicken coops and pigpens. All collecting sites monitored were found positive for sandflies. A total of 849 specimens were caught (29.2% males) belonging to five Phlebotomus species. Phlebotomus neglectus (75.6%) was the most abundant species followed by P. perfiliewi (14.4%), P. papatasi (4.6%), P. tobbi (3.6%) and P. similis (1.8%). The first adult of P. neglectus appeared on June 11 and the last one was collected on October 16. The highest density for this species was observed at the end of July. A total of 111 blood-fed females were caught from the two areas studied. P. neglectus was the only species found blood fed in Lezhe and the same species was prevalent (56.1%) in Kruje followed by P. perfiliewi (30.3%), P. tobbi (10.6%); P. papatasi was represented by only two specimens. Blood meal origin was determined in 45/66 (68.2%) of the females tested from Kruie district. P. neglectus was found fed on four hosts, showing the following feeding patterns: cow (71.4%), dog (117.1%), chicken (5.7%) and human (5.7%); P. perfiliewi was found fed on cow (80.0%) and chicken (20.0%), P. tobbi on cow (50.0%), chicken (25.0%) and dog (25.0%). One specimen of P. papatasi was found fed on cow. When such prevalences were analysed by the available biomass for each host present at the collecting site, P. neglectus resulted to be an opportunistic feeder rather than exhibiting preferences for any specific animal. PCR analysis of 39 P. neglectus from the Lezhe district gave negative results for the presence of Leishmania DNA.     

Recent findings of Phlebotomus neglectus Tonnoir, 1921 in Italy and its western limit of distribution

During the sand fly season of 2001, sand flies were collected in two different regions of Italy to investigate the northern distribution of Phlebotomus neglectus. The study areas were two provinces of northern Italy, Ivrea and Verona, in Piedmont and Veneto regions respectively. Sticky traps and CDC miniature light traps were used both inside and outside domestic and peri-domestic environments. Sand flies were also collected in domestic resting sites with mouth and electric aspirators. Of 1,295 sand fly specimens collected, 855 were from the Veneto region and 440 were from the Piedmont region. Five species of the genera Phlebotomus and Sergentomyia were identified. S. minuta (66.3%) was the most abundant sand fly followed by P. perniciosus (22.2%), P. neglectus (10.3%) and P. papatasi (1.2%). Only one specimen of P. mascittii was caught in Piedmont region. P. neglectus was found in 9 out of 15 (60%) of the sites where sand flies were found with a prevalence of 1.5% to 45.8%; the highest value was recorded in Piedmont region. P. neglectus was mostly associated with peridomestic and domestic sites. The results confirm previous observations on the presence of P. neglectus in northern Italy and suggest that this species is probably widespread in the area. From a review of all previous published and unpublished records of P. neglectus, it appears that this species is present in only two areas of the country, namely in the regions of Friuli Venezia Giulia, Veneto and Piedmont in northern Italy and the regions of Calabria, Apulia and Sicily in southern Italy. The apparent absence of P. neglectus in Central Italy is discussed and the resulting settlement through two probable migration routes from the East is analysed.     

5-Methyl-2-phenyl-2-hexenal in the scent gland secretion of male cave crickets,Troglophilus cavicola and T. neglectus (Ensifera: Rhaphidophoridae)

5-Methyl-2-phenyl-2-hexenal, a distinctly smelling compound, was identified as a constituent of the male scent gland secretion of two species of cave crickets, Troglophilus cavicola and T. neglectus. It is the first proof of a male specific exocrine compound in grasshoppers. A pheromonal function of the component could not be established; its possible biological role is discussed.     

Cultivable microscopic fungi from an underground chemosynthesis-based ecosystem: a preliminary study

Movile Cave, a unique groundwater ecosystem in southern Romania, was discovered in 1986. This chemoautotrophic cave contains an abundant and diverse fauna with terrestrial and aquatic invertebrate communities, including 33 endemic species. Since its discovery, studies have focused mainly on cave chemoautotrophic bacteria, while the microfungal community has been largely neglected. In this study, we determined the microfungal species living on various substrates in Movile Cave and compared this spectrum with the mycobiota detected outside the cave (outside air-borne and soil-borne microfungi). To investigate all of the niches, we collected samples for two consecutive years from the dry part of the cave (cave air and sediment, corroded limestone walls, isopod feces, and isopod and spider cadavers) and from the post-siphon part of the cave, i.e., Airbell II (sediment and floating microbial mat). A total of 123 microfungal species were identified from among several hundred isolates. Of these, 96 species were only detected in the cave environment and not outside of the cave, while 90 species were from the dry part of the cave and 28 were from Airbell II. The most diverse genera were Penicillium (at least 18 species) and Aspergillus (14 species), followed by Cladosporium (9 species). Surprisingly, high CFU counts of air-borne microfungi were found inside the cave; they were even higher than outside the cave during the first year of investigation.     

Is Competition with the Invasive Crayfish Orconectes neglectus chaenodactylus Responsible for the Displacement of the Native Crayfish Orconectes eupunctus?

The crayfish Orconectes eupunctus, a species of special concern, appears to have been displaced from part of its former range in the Spring River drainage of Arkansas and Missouri by the invasive crayfish O. neglectus chaenodactylus. We conducted preliminary field experiments to determine whether Orconectes eupunctus were displaced from their former range and whether interspecific competition with O. neglectus chaenodactylus was responsible for the displacement. To determine whether Orconectes eupunctus were displaced from their former range by negative biotic interactions with other species we placed single adult male O. eupunctus in cages at two sites: an upstream site where O. eupunctus was formerly abundant and a downstream site where it is currently abundant. Orconectes neglectus chaenodactylus were additionally paired alongside O. eupunctus at the upstream site. We also conducted a field competition experiment with treatments consisting of (1) 3 O. eupunctus, (2) 6 O. eupunctus, and (3) 3 O. eupunctus and 3 O. neglectus chaenodactylus at a site where both species occur. In the first experiment, O. eupunctus gained significantly more weight at the downstream site than the upstream site during 2003, but not during 2002. At the upstream site, O. eupunctus showed significantly greater growth rates than O. neglectus chaenodactylus during 2002, but not during 2003. In the competition experiment, O. neglectus chaenodactylus did not significantly reduce the growth or survival of O. eupunctus. These results suggest that O. eupunctus have been displaced from their former range by biotic interactions, but interspecific competition between adult male O. eupunctus and O. neglectus chaenodactylus does not appear to be the mechanism responsible for this displacement. Further study is needed to investigate the disappearance of O. eupunctus.     

Greater impact of host plant species on oviposition of a willow leaf beetle <Emphasis Type="Italic">Plagiodera versicolora</Emphasis> Laicharting (Coleoptera: Chrysomelidae) during the adult stage than in developing larval stage

In some herbivorous insects, such as Coleoptera and aphids, not only the host species of larvae, but also those of adults should be considered as key determinants of potential fecundity because oviposition is affected by the quality of host species during both larval and adult stages. This study examined the relatively greater impact on host species of the larval or adult stage on oviposition of the willow leaf beetle Plagiodera versicolora Laicharting (Coleoptera: Chrysomelidae). We conducted an experiment using a 2 × 2 experimental design, in which either of two different host plant species was fed in larval and adult stages. Females fed on a locally unavailable host Salix eriocarpa in the adult stage did not lay any eggs, but those fed on the locally available host S. babylonica laid 67–75 eggs on average, irrespective of larval host species. Such reproductively inactive females fed S. eriocarpa as an adult host recovered reproductive activity within 3 weeks after changing the host species to S. babylonica. This result indicated that the host species fed in the adult stage had a greater impact on oviposition than in the larval stage.     

Comparative Evaluation of the Gut Microbiota Associated with the Below- and Above-Ground Life Stages (Larvae and Beetles) of the Forest Cockchafer,Melolontha hippocastani

A comparison of the diversity of bacterial communities in the larval midgut and adult gut of the European forest cockchafer (Melolontha hippocastani) was carried out using approaches that were both dependent on and independent of cultivation. Clone libraries of the 16S rRNA gene revealed 150 operational taxonomic units (OTUs) that belong to 11 taxonomical classes and two other groups that could be classified only to the phylum level. The most abundant classes were β, δ and γ-proteobacteria, Clostridia, Bacilli, Erysipelotrichi and Sphingobacteria. Although the insect’s gut is emptied in the prepupal stage and the beetle undergoes a long diapause period, a subset of eight taxonomic classes from the aforementioned eleven were found to be common in the guts of diapausing adults and the larval midguts (L2, L3). Moreover, several bacterial phylotypes belonging to these common bacterial classes were found to be shared by the larval midgut and the adult gut. Despite this, the adult gut bacterial community represented a subset of that found in the larvae midgut. Consequently, the midgut of the larval instars contains a more diverse bacterial community compared to the adult gut. On the other hand, after the bacteria present in the larvae were cultivated, eight bacterial species were isolated. Moreover, we found evidence of the active role of some of the bacterial species isolated in food digestion, namely, the presence of amylase and xylanolytic properties. Finally, fluorescence in situ hybridization allowed us to confirm the presence of selected species in the insect gut and through this, their ecological niche as well as the metagenomic results. The results presented here elucidated the heterogeneity of aerobic and facultative bacteria in the gut of a holometabolous insect species having two different feeding habits.     

A comparison of superoxide dismutase (SOD, EC:1.15.1.1) distribution in gastro-intestinal nematodes.

An examination of the distribution of superoxide dismutase (SOD) activities in whole worm homogenates from six gastro-intestinal nematodes, at different life-cycle stages, demonstrated that the third larval stages of each species contained notably more activity than the corresponding adults. Significant SOD activities were detected in culture fluids following in vitro maintenance of third and fourth larval stage and adult Trichostrongylus vitrinus and Teladorsagia circumcincta (formerly Ostertagia circumcincta). Marked interspecies variation was observed when SOD isoenzyme profiles of adult and third larval stage Nippostrongylus brasiliensis, Trichostrongylus vitrinus, Teladorsagia circumcincta and Haemonchus contortus were compared. In addition, SOD activity and isoenzyme polymorphism were greater in Nippostrongylus brasiliensis harvested from primed rats compared to parasites recovered from naive rats.     

Ontogeny of sexual dimorphism and phenotypic integration in heritable morphs

In this study we investigated the developmental basis of adult phenotypes in a non-model organism, a polymorphic damselfly (Ischnura elegans) with three female colour morphs. This polymorphic species presents an ideal opportunity to study intraspecific variation in growth trajectories, morphological variation in size and shape during the course of ontogeny, and to relate these juvenile differences to the phenotypic differences of the discrete adult phenotypes; the two sexes and the three female morphs. We raised larvae of different families in individual enclosures in the laboratory, and traced morphological changes during the course of ontogeny. We used principal components analysis to examine the effects of Sex, Maternal morph, and Own morph on body size and body shape. We also investigated the larval fitness consequences of variation in size and shape by relating these factors to emergence success. Females grew faster than males and were larger as adults, and there was sexual dimorphism in body shape in both larval and adult stages. There were also significant effects of both maternal morph and own morph on growth rate and body shape in the larval stage. There were significant differences in body shape, but not body size, between the adult female morphs, indicating phenotypic integration between colour, melanin patterning, and body shape. Individuals that emerged successfully grew faster and had different body shape in the larval stage, indicating internal (non-ecological) selection on larval morphology. Overall, morphological differences between individuals at the larval stage carried over to the adult stage. Thus, selection in the larval stage can potentially result in correlated responses in adult phenotypes and vice versa.     

光滑足距小蠹虫道真菌的组成和变化

本文同时采用分离和电镜扫描技术研究了光滑足距小蠹Xylosandrus germanus(Blan dford)不同发育阶段坑道和贮菌器内真菌种类的组成和变化。Ambrosiella hartigii是光滑足距小蠹扩散、蛀孔、越冬和体壁新硬化的成虫贮菌器内唯一分离到的真菌,而刚羽化的雌成虫贮菌器中没有分离到任何真菌种类,体壁新硬化的成虫贮菌器中真菌的分离频率最低。坑道内共分离到4种真菌：A. hartigii,Acremonium kiliense和2种镰刀菌Fusarium spp.。从卵期到蛹期的坑道中,A. hartigii总是能被分离到,占分离物总数的百分率较高,达40％～60％;而在成虫期坑道中,A. kiliense和Fusarium sp.1被分离率较高,都为34.6％。扫描电镜观察表明,A. hartigii为卵期到蛹期坑道中的优势种,而镰刀菌Fusarium spp.则是成虫期坑道中的优势种。这些结果均表明,Ambrosiella hartigii,Acremonium kiliense和2种镰刀菌Fusarium spp.是光滑足距小蠹的虫道真菌,而且这些真菌种类组成和优势种类是随着蠹虫的发育阶段而变化的。真菌种类的组成和变化可 能与幼虫和成虫的营养需求以及虫道真菌的生长特性有关。     

栎黄枯叶蛾生长发育与几种寄主内含物的关系

【目的】探讨饲喂不同寄主植物对栎黄枯叶蛾Trabala vishnou gigantina Yang生长发育及繁殖的影响,分析寄主植物内含物与其生长发育及繁殖的关系,为研究不同寄主植物对栎黄枯叶蛾种群动态的影响提供理论依据。【方法】在室内条件下,利用沙棘Hippophae rhamnoides、山杏Armeniaca sibirica、山杨Populus davidiana、旱柳Salix matsudana饲养该虫,观察幼虫发育历期、蛹历期、蛹重及产卵量等指标,同时测定寄主叶片中可溶性糖、可溶性蛋白质、水分、单宁及黄酮的含量,并进行线性回归分析。【结果】不同寄主植物饲喂栎黄枯叶蛾幼虫的发育历期、蛹历期、蛹重及产卵量均存在显著差异。取食沙棘的幼虫历期最短,仅为(74.50?1.76)d,而取食旱柳历期最长,达(106.00?1.51)d。取食山杨的蛹历期最长,为(44.00?1.41)d,最短的是取食旱柳的,仅为(32.70?3.13)d。饲喂沙棘和山杏的雌、雄蛹重和成虫产卵量显著高于饲喂山杨和旱柳的。对不同寄主的营养物质、次生物质和水分含量测定结果表明:不同寄主间营养物质、次生物质与水分的含量差异显著。回归相关分析表明:幼虫发育历期与寄主植物可溶性蛋白质含量呈显著负相关;雌蛹重和产卵量与寄主植物可溶性糖含量呈显著负相关;雌、雄蛹重与寄主植物含水量呈显著正相关;蛹历期与单宁含量呈显著正相关,但黄酮含量的高低与栎黄枯叶蛾生长发育等指标无相关性。【结论】沙棘是栎黄枯叶蛾生长发育及繁殖的最适寄主植物;并且寄主植物中可溶性糖、单宁的含量低、含水量和可溶性蛋白质含量高有利于栎黄枯叶蛾的生长发育和繁殖。     

In vivo and in vitro metacyclogenesis tests of two strains of Trypanosoma cruzi in the triatomine vectors Triatoma pseudomaculata and Rhodnius neglectus: short/long-term and comparative study

Metacyclogenesis of Trypanosoma cruzi of the Y and Berenice strains was studied in Triatoma pseudomaculata and Rhodnius neglectus. Results in vivo showed a higher production of metacyclic trypomastigotes in R. neglectus' digestive tube than in T. pseudomaculata. In vitro experiments were also carried out in order to compare the behavior of culture forms of T. cruzi incubated in extracts of different compartments (stomach, intestine, and rectum) of the digestive tract of both species of triatomines. A higher percentage of metacyclic trypomastigotes for both parasite strains, Y and Berenice, was detected in the rectum extract of R. neglectus in comparison to that from T. pseudomaculata. The same results were obtained with in vitro experiments, using parasites incubated in urine from each of those vectors. The adhesion of parasites to the incubated rectum epithelial cells was also compared. In incubations with the Y strain no significant differences were detected between the two triatomine species but, however, with the Berenice strain the mean percentage of cells with adhered parasites was higher in R. neglectus than in T. pseudomaculata.     

肠道共生细菌预发酵鸡粪对黑水虻生长发育的影响

以利用黑水虻Hermetia illucens L.肠道共生细菌不同菌株培养液预发酵的鸡粪为培养料,研究了添加不同菌株的发酵鸡粪对黑水虻幼虫生长发育的影响。结果表明,添加不同菌株的预发酵鸡粪能显著增加预蛹和蛹的重量,显著提高化蛹率并增加雌、雄成虫体长,缩短预蛹所需时间,但对幼虫存活率、成虫羽化率、成虫寿命没有显著影响。同时,不同菌株的作用效果有所不同。     

A 5000-YEAR FOSSIL RECORD OF LARVAL SHELL MORPHOLOGY OF SUBMARINE CAVE MICROSHELLS

A 5000-year fossil series of minute submarine cave bivalves was studied using morphometric and evolutionary analyses. The obtained results indicate that the shapes of larval shells of studied species were labile, whereas the size of the larval shell was stable in each species studied. This result is different than that previously reported in most other studies in which size change is more common than shape change. This unique evolutionary pattern of these bivalves might be attributed to their refugial lifestyle.     

Neotropical Copestylum Macquart (Diptera: Syrphidae) Breeding in Fruits and Flowers,Including 7 New Species

Ten species of Copestylum (Diptera: Syrphidae) were reared from fruits and flowers in Costa Rica, Ecuador and Trinidad. Seven were new and in this paper, we describe them, their development sites and the third stage larva and/or the puparium of all ten species. One new synonym is proposed, Copestylum pinkusi (Curran) [= Copestylum cinctiventre (Curran)]. Similarities and differences between these new and other Copestylum species, suggest they separate into two groups, referred to as the Vagum and Cinctiventre species groups. Features characterising these groups for both adult and early stages are assessed. Each species was also distinguished using adult and early stage characters. Within the Vagum group, adults were more disparate morphologically than the larval stage; this was reversed in the Cinctiventre group. Adult colour patterns are probably cryptic in function and for disguise. Vagum species have disruptive marks, while the Cinctiventre species have reflective colours. Biologically, the groups are almost distinguished by larval development sites. Vagum species use predominantly fruits and have a larval stage that is relatively generalised in form and habit. Cinctiventre species are confined to developing in flowers and the larva is more specialised. A key to both adult and early stages of all ten species is provided.     

Life cycle and host specificity of Amblyomma triste (Acari: Ixodidae) under laboratory conditions

We report biological data of two generations of Amblyomma triste in laboratory and compared the suitability of different host species. Infestations by larval and nymphal stages were performed on guinea pigs (Cavia porcellus), chickens (Gallus gallus), rats (Rattus norvegicus), rabbits (Oryctolagus cuniculus), wild mice (Calomys callosus), dogs (Canis familiaris) and capybaras (Hydrochaeris hydrochaeris). Infestations by adult ticks were performed on dogs, capybaras and rabbits. Tick developmental periods were observed in an incubator at 27 degrees C and RH 90%. Guinea pigs were the most suitable hosts for larvae and nymphs, followed by chickens. The remaining host species were less suitable for immature ticks as fewer engorged ticks were recovered from them. Mean larval feeding periods varied from 3.8 to 4.7 d between different host species. Mean larval premolt periods ranged from 8.9 to 10.4 d. Nymphal mean feeding periods varied from 4.2 to 6.2 d for ticks fed on different host species. Premolt period of male nymphs (mean: 15.4 d) was significantly longer than that of female nymphs (14.7 d). Female nymphs were significantly heavier than male nymphs. The overall sex ratio of the adult ticks emerged from nymphs was 0.9:1 (M:F). Capybaras were the most suitable host for the tick adult stage as significantly more engorged females were recovered from them and these females were significantly heavier than those recovered from dogs or rabbits. The life cycle of A. triste in laboratory could be completed in an average period of 155 d. The potential role of guinea pigs, birds and capybaras, as hosts for A. triste in nature, is discussed.