Life-history and sex allocation in Trypoxylon (syn. Trypargilum) lactitarse (Hymenoptera; Crabronidae)

Hymenopterans have become a model for the study of factors that govern sex allocation. In 1983, Seger proposed a model to study Sphecidae wasps with a strong prediction that sex ratio for univoltine wasps should be 1 : 1 (female : male), and for partially bivoltine species it should be male-biased. The present study investigates if Trypoxylon lactitarse (Saussure, 1867) is a univoltine or a bivoltine species and if Seger's model prediction fits the pattern of sex ratio found in this species. The study was carried out at Parque Municipal das Araucárias, in the municipality of Guarapuava, state of Paraná, southern Brazil, from December 2001 to December 2004. Nests of T. lactitarse were obtained using trap-nests drilled longitudinally to a depth to 80 mm with 7.0, 10.0 and 13.0 mm opening diameter. They were placed in a very heterogeneous site filled with araucaria forests, swamps and grasslands. Trypoxylon lactitarse showed two alternative life histories: either they pupated immediately and emerged as adults later in the same season (direct development), or they entered diapause, overwintering and pupating the following spring (delayed development). Its annual sex ratios were not significantly different from 1 : 1, and both sex ratio of overwintering and sex ratio of direct-developing wasps were also not significantly different from 1 : 1, in all years of this study. By examining these results, it was possible to conclude that although T. lactitarse is a multivoltine species, with four generations per year and two alternative life histories, its sex ratio did not support Seger's model.     

A Review of the Genus Eucnemis Ahrens, 1812 (Coleoptera,Eucnemidae) from Russia

Entomological Review - The genus Eucnemis Ahrens, 1812 of the Russian fauna is revised. A new species, Eu. anachoreta sp. n. is described from Kunashir Island, the Kuril Archipelago. A key to the...     

Genetic architecture of survival and fitness-related traits in two populations of Atlantic salmon

The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non-additive genetic and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non-additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss whether the similarities in architectures of these populations is the result of natural selection across a common juvenile environment.     

Conservation of rare species with island-like distributions: A case study of Lasthenia conjugens (Asteraceae) using population genetic structure and the distribution of rare markers

Californian vernal pools, a patchy, island-like habitat, are endangered as a result of habitat destruction. Conservation of the remaining vernal pool habitat is essential for the persistence of several endangered species. We present the first study examining DNA-level genetic diversity within and among populations of a vernal pool plant species. We investigated genetic variation across eight populations of the US federally endangered vernal pool endemic Lasthenia conjugens (Asteraceae) using intersimple sequence repeat (ISSR) markers. Genetic diversity within the species was high (Nei's gene diversity estimate was 0.37), with moderate differentiation among populations (Bayesian F _ST analog of 0.124). Using an amova analysis, we found that the majority of the genetic variation (84%) was distributed within populations. There is a significant relationship between geographical distance and pairwise genetic differentiation as measured by the Bayesian estimate θ^B. The alternative hypotheses of historic geological processes within the Central Valley and contemporary gene flow are discussed as explanations of the data. Because of the vulnerability of the populations, we calculated a probability of loss for rare alleles (fragments) in the populations. Calculations show that sampling only one of the eight populations for ex-situ conservation or restoration will capture approximately 54% of the sampled rare fragments. We believe that one of the sampled populations has become extinct since it was sampled. When removing this population from the above-mentioned calculations, sampling one population will capture only 41.3% of the sampled rare fragments. We recommend sampling strategies for future conservation and restoration efforts of L. conjugens.     

Mitochondrial markers reveal deep population subdivision in the European protected spider <Emphasis Type="Italic">Macrothele calpeiana</Emphasis> (Walckenaer, 1805) (Araneae,Hexathelidae)

The funnel-web spider genus Macrothele is the only representative of the mygalomorph family Hexathelidae not found in Australia or New Zealand. Its 26 species occur in Central Africa and the Oriental region. Two Macrothele species are found in Europe: M. cretica Kulczynski, 1903 from Crete, and M. calpeiana (Walckenaer, 1805) type species of the genus and the largest European spider, whose distribution extends across the south-eastern Iberian Peninsula, and in two localities of North Africa. Macrothele calpeiana is the only spider protected under European legislation. The fragmentation and destruction of the cork oak forest, with which M. calpeiana was thought to be closely associated, prompted the inclusion of this species in the Bern Convention. Some authors, however, have challenged this view and consider M. calpeiana to be neither a cork oak forest bioindicator nor an endangered species. By contrast, other observations suggest that the distribution of the species is extremely fragmented and that most local populations should be considered as threatened. In this paper, we examine aspects of the conservation status of M. calpeiana in the light of molecular phylogenetic analyses based on mitochondrial markers of sample specimens from major populations. Our data confirm the fragmented distribution of M. calpeiana and reveal high levels of genetic differentiation across its populations. Local population growth cannot be ruled out, though the lineage as a whole has apparently not undergone population growth. Lineage age estimates suggest that M. calpeiana colonized the Iberian Peninsula during the Messinian salinity crisis and that the current population fragmentation originates from the Pliocene and Pleistocene. We argue that the fragmentation and deep genetic divergence across populations, along with evolutionary singularity and endemicity in one of Europe’s main biodiversity hotspots, support the preservation of its legally protected status.     

Ecological exchangeability versus neutral molecular markers: the case of the great tit

Neutral genetic markers, such as mitochondrial DNA (mtDNA) sequences, are commonly used to discover independently evolving groups of populations in nature. These groups are often considered to be units of conservation because they preserve distinct organismal histories. However, because of the time lag between the isolation of populations and the evolution of diagnostic neutral markers, adaptive traits could be unrepresented by units defined by neutral markers. The concept of ecological exchangeability potentially provides a way to preserve populations possessing local adaptations that lack diagnostic neutral markers. Populations are surveyed for differences in fitness traits, either directly, or by examining morphological or genetic traits that could indirectly serve as proxies for them. The purpose of this paper is to compare the nature of units of conservation defined by neutral gene surveys and ecological exchangeability, using data recently available for the great tit Parus major , a wide-ranging Palearctic species. mtDNA surveys reveal a lack of differentiation across thousands of kilometer. In contrast, studies of body size and clutch size show locally adapted differences between populations separated by a few kilometer, meaning that these populations could be classified as ecologically in exchangeable. These two types of markers have dramatically different consequences for the geographic and evolutionary scale of conservation units. The concept of ecological exchangeability might be an inappropriate way to diagnose units of conservation in birds owing to the time required to document local adaptations and their potential ubiquity. Neutral genetic markers continue to provide a theoretically sound way of identifying units of conservation, and these units ought to be integrated into conservation plans without delay.     

Life-history responses of larviparous Boettcherisca formosensis (Diptera: Sarcophagidae) to larval competition for food, including comparisons with oviparous Hemipyrellia ligurriens (Calliphoridae)

Abstract. 1 The effect of larval rearing density on life-history parameters of Boettcherisca formosensis Kirner & Lopes (Sarcophagidae) was investigated. Increases in rearing density resulted in lowered larval survivorship, shortened larval development time and production of smaller, shorter-lived adults with reduced fecundity.
2. B. formosensis is larviparous. Average brood size was 17.5±1.0 (mean±M) larvae, which was much less than the average number of mature larvae inside gravid females. Females apparently produced a series of small broods, distributing their offspring over a number of carcasses.
3. Compared with the oviparous species Hemipyrellia ligurriens (Wiedemann) (Calliphoridae), B. formosensis adults were larger and longer-lived, with a longer larval development time but shorter larval feeding period. However, females had a shorter pre-reproductive period, were less fecund, and had a lower life time reproductive investment.
4. B. formosensis had lower relative performance (measured by the composite index of performance, r') than H. ligurriens over the larval rearing density range, and was more sensitive to increases in density. Although the r' values suggest that the sarcophagid may be a competitively inferior species, other features which are not included in the index (such as larvipary, short larval feeding period and spreading of offspring from a single brood among carcasses) may be of significant adaptive value to B. formosensis.     

Microsatellite markers for eastern hemlock (Tsuga canadensis)

We describe polymerase chain reaction primer pairs and reaction conditions for amplification of 15 microsatellite loci from eastern hemlock (Tsuga canadensis). The primers were tested on 23 individuals from a natural population in southwestern North Carolina, USA. These primers yielded an average of 5.9 alleles per locus (range of 2-14), an average observed heterozygosity of 0.45 (range 0.14-0.73), and an average polymorphic information content of 0.54 (range 0.28-0.86). In addition, eight of the primer pairs were found to amplify microsatellite loci in one or more additional species of Tsuga.     

Isolation and characterization of microsatellite markers for Araucaria angustifolia (Araucariaceae)

Araucaria angustifolia is a dioecious tree species that occurs in the southern part of Brazil. Because of the intense exploitation of the species due to its valuable wood, only 2% of the original population still remains. Twenty‐nine species‐specific and highly polymorphic microsatellite loci were developed from a genomic library enriched for AG/TC repeats. Levels of polymorphism were evaluated using a total of 16 adult trees from a natural population. An average of 8.1 alleles per locus was detected, and expected heterozygosity ranged from 0.63 to 0.72.     

A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei,Atherinopsidae) from Southern Brazil

Da Silva Cortinhas, M. C., Glienke, C., Prioli, A. J., Noleto, R. B., Matoso, D. A. and Cestari, M. M. 2010. A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei, Atherinopsidae) from Southern Brazil. —Acta Zoologica (Stockholm) 91 : 242–248 As a result of the importance of Atherinella brasiliensis in estuarine environments, random amplified polymorphic DNA (RAPD) markers were used to verify the genetic diversity in A. brasiliensis from two different places in Paranaguá Bay (Paraná State) and one from the Conceição Lagoon (Santa Catarina State). Cytogenetic data have shown a high karyotypic diversity in some populations, although in others this peculiarity demonstrates rearrangements such as heterochromatinization. In the present study, a low level of genetic structuring between the samples from Conceição Lagoon compared with the others was observed through principal coordinate analysis (PCO), analysis of molecular variance and Mantel test according to 79 RAPD markers. As this specie does not perform horizontal migration and the individuals of Conceição Lagoon are isolated, three hypotheses are proposed to explain the results: (i) similar environments may show homogeneous populations not depending on the geographical distance, (ii) because vicariant events that formed the bays occurred in a recent period, the fragmentation effects over the structuring of the genetic diversity may still be low and not totally detectable by the RAPD technique and (iii) the isolation time or the number of generations may not be enough to promote a possible differentiation and genetic structuring between the specimens of these three places. The specimens of these places present a low level of differentiation and genetic structuring so we can consider them as a unique homogeneous population.     

Covariation in Insular Life-history Traits of the Rice Frog(Fejervarya limnocharis)in Eastern China

Although shifts in life-history traits of insular vertebrates, as compared with mainland populations, have been observed in many taxa, few studies have examined the relationships among individual life-history traits on islands. Lifehistory theory also predicts that there is a trade-off between body size and reproductive effort, and between egg size and clutch size. We surveyed the rice frog, Fejervarya limnocharis, on 20 islands within the Zhoushan Archipelago and two nearby sites on the mainland of China to compare differences in life-history traits and to explore relationships among those traits. Rice frog females reached a greater body size on half of the smaller islands among the total 20 surveyed islands, and larger egg size, decreased clutch size and reduced reproductive effort on most of the islands when compared to the two mainland sites. Insular body size was negatively correlated with reproductive effort. There was a negative correlation between egg size and clutch size. Results suggest that life-history theory provides a good explanation for co-variation between body size and reproductive effort, and between egg size and clutch size in rice frogs on the islands.