Quarantine host range of Bikasha collaris,a potential biological control agent of Chinese tallowtree (Triadica sebifera) in North America

Chinese tallowtree, Triadica sebifera (L.) Small (Euphorbiaceae), is one of the worst invasive weeds of the southeastern USA impacting coastal wetlands, forests, and natural areas. Traditional mechanical and chemical controls have been unable to limit the spread, and this invasive species continues to expand its range. A proposed biological control candidate, the flea beetle Bikasha collaris (Baly) (Coleoptera: Chrysomelidae), shows high specificity for the target weed Chinese tallowtree. Results from a series of no‐choice and choice feeding tests of B. collaris adults and larvae indicated that this flea beetle was highly specific to Chinese tallowtree. The larvae of B. collaris feed by tunneling in the roots, whereas the adults feed on the leaves of Chinese tallowtree. A total of 77 plant taxa, primarily from members of the tallow plant family Euphorbiaceae, were tested in numerous test designs. Larval no‐choice tests indicated that larvae completed development only on two of the non‐target taxa. Of 80 B. collaris larvae fed roots of Hippomane mancinella L. and 50 larvae fed roots of Ricinus communis L., two and three larvae completed development, respectively. The emerging adults of these five larvae died within 3 days without reproducing. Larval choice tests also indicated little use of these non‐target taxa. Adult no‐choice tests indicated little leaf damage by B. collaris on the non‐targets except for Ditrysinia fruticosa (Bartram) Govaerts & Frodin and Gymnanthes lucida Sw. When given a choice, however, B. collaris adults consumed much less of the non‐targets D. fruticosa (7.4%) and G. lucida (6.1%) compared with the control leaves. Finally, no‐choice oviposition tests indicated that no eggs were produced when adults were fed all non‐target taxa, except those fed G. lucida. These B. collaris adults fed G. lucida leaves produced an average of 4.6 eggs compared with 115.0 eggs per female when fed Chinese tallowtree. The eggs produced from adults fed G. lucida were either inviable or the emerging larvae died within 1 day. These results indicate that the flea beetle B. collaris was unable to complete its life cycle on any of the non‐target taxa tested. If approved for field release, B. collaris will be the first biological control agent deployed against Chinese tallowtree in the USA. This flea beetle may play an important role in suppressing Chinese tallowtree and contribute to the integrated control of this invasive weed.     

Life history and host range of Sauris nr. purpurotincta,an unsuitable biological control agent for Chinese tallowtree

Foreign surveys in China discovered a defoliating insect species feeding on the leaves of Chinese tallowtree (Triadica sebifera), an invasive weed of the southeastern U.S.A. The life history of this species, Sauris nr. purpurotincta (Lepidoptera: Geometridae), was examined and larval no-choice and adult multiple-choice host range tests were conducted in quarantine to evaluate their suitability for biological control of Chinese tallowtree. The results indicated that the larvae have five instars and require approximately 22 days to complete development to the adult stage. Host range tests indicated that the larvae could not feed and complete development on most species tested. However, 40% of the larvae survived when fed leaves of Hippomane mancinella, a state-listed endangered species in Florida, and all larvae survived when fed Morella cerifera, a common native species of the southeastern U.S.A. Multiple-choice oviposition tests indicated eggs were laid on leaves of both a south Florida native plant Gymnanthes lucida and Chinese tallowtree. Considering this broad host range, this species will not be considered further for biological control of Chinese tallowtree in the U.S.A.     

Morphophysiological,ultrastructural, and nutritional changes induced by Cu toxicity in young Erythrina fusca plants

Erythrina fusca is an important legume used for shade cover in cacao plantations in Brazil. Cacao plantations receive large quantities of copper (Cu)-containing agrochemicals, mainly for control of diseases. Therefore, Cu toxicity was investigated in seedlings grown in hydroponics with increasing concentrations of Cu (0.005–32 mg L^?1) in a greenhouse. Ultrastructural analyses showed cell plasmolysis in the root cortical area and changes in thylakoid membranes at 8 mg Cu L^?1 and higher. There were changes in epicuticular wax deposition on the leaf surface at the 16 and 32 mg Cu L^?1 treatments. Leaf gas exchanges were highly affected 24 hours after application of treatments beginning at 8 mg Cu L^?1 and higher Cu concentrations. Chemical analyses showed that Cu content in E. fusca roots increased as Cu concentration in the nutrient solution increased, whereas the shoot did not show significant changes. It is also observed that excess Cu interfered with Zn, Fe, Mn, Mg, K, P, and Ca content in the different E. fusca organs. Investigation of Cu toxicity symptoms focusing on morphophysiological, ultrastructural, gas exchange, and nutritional changes would be useful to alleviate Cu toxicity in E. fusca under field conditions, an important agroforestry species in cacao plantation.     

Characterization of eight microsatellite loci in the maize stalk borer Busseola fusca Fuller, 1901 (Lepidoptera: Noctuidae)

The noctuid stem borer Busseola fusca occurs throughout sub‐Saharan Africa, where it is considered as a major pest of corn and sorghum. To understand B. fusca phylogeography, we isolated and characterized eight microsatellite loci in this species. We investigated these loci for polymorphism on a subset sample of individuals from different geographic populations. All loci were polymorphic, showing between four and 10 alleles. Cross‐species amplification of four of these loci was tested on 11 other noctuid species.     

A role for both ecology and geography as mechanisms of genetic differentiation in specialized butterflies

An important mechanism of speciation for specialized phytophagous insects is host-associated differentiation, in which natural selection drives the evolution of reproductive isolation. Here we use molecular population genetics data to test the hypothesis that regional and local specialization on three alternate hosts restricts gene flow in the Mitoura gryneus species complex of butterflies. Over half of the variation in mitochondrial DNA sequences is explained by host plant association (?_CT = 0.57, P = 0.002) consistent with the hypothesis of host-associated divergence on the three hosts. AFLP analyses revealed the number of clusters of individuals was K = 2, with all individuals associated with one host grouping separately from all other host-associated individuals. Combined with previous experimental results, these findings present evidence of varying levels of differentiation among host associations and identify a role for both isolation in allopatry as well as ecological factors in limiting gene exchange. The Mitoura species complex includes multiple, differentiated lineages at varying stages of divergence, providing an opportunity to examine the multifarious mechanisms that generate biodiversity in phytophagous insects.     

Low levels of genetic variation within populations of the four rare orchids Gymnadenia cucullata, Gymnadenia camtschatica, Amitostigma gracile, and Pogonia minor in South Korea: indication of genetic drift and implications for conservation

Many terrestrial orchids are relatively rare, and their populations are small and spatially isolated. Population genetics theory predicts that populations of such species, affected historically by random genetic drift, would maintain low levels of genetic diversity and exhibit a high degree of among-population divergence. To test this prediction, I used enzyme electrophoresis. Genetic diversity within populations of the four rare, terrestrial orchids Gymnadenia cucullata (four populations) and its congener G. camtschatica (four populations), Amitostigma gracile (four populations in one region and three in another region), and Pogonia minor (three populations each in two regions) was investigated in South Korea at the landscape level. As predicted, populations of the four species harbor low levels of genetic diversity within populations: the mean percentage of polymorphic loci, %P, the mean number of alleles per locus, A, and the average expected heterozygosity, H _e, were 12.5%, 1.13, and 0.036 for G. cucullata, respectively; 18.2%, 1.18, and 0.067 for G. camtschatica; 3.0%, 1.04, and 0.009 for A. gracile; and 2.7%, 1.06, and 0.014 for P. minor. Except for G. camtschatica (F _ST = 0.000), a significantly high degree of genetic divergence between conspecific populations was detected in the other three species: F _ST = 0.081 for G. cucullata; 0.348 and 0.811 in two regions for A. gracile; and 0.469 and 0.758 in two regions for P. minor. In addition, individuals within populations are highly structured in the four species (overall F _IS = 0.276 for G. cucullata; 0.308 for G. camtschatica; 0.758 for A. gracile; and 0.469 for P. minor), suggesting that selfing, biparental inbreeding, and/or consanguineous mating have occurred in populations of the four species. With the exception of G. camtschatica, an allele at a locus is fixed in a population, whereas alternative alleles with low or high frequencies are detected in another population across the landscape. My results suggest that evolutionary histories of G. cucullata, A. gracile, and P. minor are different from G. camtschatica. Historical genetic drift would be an important force shaping the genetic structure of the Korean populations of G. cucullata, A. gracile, and P. minor. For G. camtschatica on Ulleung Island, relatively higher levels of genetic variation within populations compared to its congener G. cucullata (H _e = 0.067 vs. 0.036) and little evidence of population genetic structure among populations (F _ST = 0.000) suggest that individuals were, presumably, once continuously distributed on Ulleung Island, and populations have recently been isolated by habitat fragmentation through natural succession (e.g,. probably the encroachment of woody vegetation on grasslands) or human-mediated disturbances (e.g., collections). Thus, conservation strategies for the four species should be differently developed in order to preserve genetic diversity in South Korea.     

Phylogeography of <Emphasis Type="Italic">Eleotris fusca</Emphasis> (Teleostei: Gobioidei: Eleotridae) in the Indo-Pacific area reveals a cryptic species in the Indian Ocean

Indo-Pacific insular freshwater systems are mainly dominated by amphidromous species. Eleotris fusca is a widespread one, its life cycle is characterised by a marine pelagic larval phase allowing the species to disperse in the ocean and then to recruit to remote island rivers. In the present study, the population structure of E. fusca over its Indo-Pacific distribution range (Western Indian Ocean to French Polynesia, Pacific Ocean) was evaluated. We analysed a section of mitochondrial COI of 557 individuals sampled from 28 islands to visualise the population structure. Haplotypes diversity (Hd) was between 0.458 and 1 and, nucleotide diversity (π) was between 0.001 and 0.02. Two distinct genetic groups appeared, one in the Indian Ocean and the other in the Pacific Ocean (F_ST mean?=?0.901; 5.2% average divergence). Given these results, complete mitogenomes (mtDNA) were sequenced and combined with the nuclear Rhodopsin (Rh) gene for a subset of individuals. The two phylogenetic trees based on each analysis showed the same genetic pattern: two different groups belonging to the Indian and the Pacific oceans (6.6 and 1.6% of divergence for mtDNA and Rh gene respectively), which supported species level differentiation. These analyses revealed the presence of two sister species confounded until present under the name of Eleotris fusca. One of them is cryptic and endemic of the Indian Ocean and the other one is the true E. fusca, which keeps, nevertheless, its status of widespread species.     

The effects of diadromy and its loss on genomic divergence: The case of amphidromous Galaxias maculatus populations

Understanding the evolutionary mechanisms that affect the genetic divergence between diadromous and resident populations across heterogeneous environments is a challenging task. While diadromy may promote gene flow leading to a lack of genetic differentiation among populations, resident populations tend to be affected by local adaptation and/or plasticity. Studies on these effects on genomic divergence in nonmodel amphidromous species are scarce. Galaxias maculatus, one of the most widespread fish species in the Southern Hemisphere, exhibits two life histories, an ancestral diadromous, specifically, amphidromous form, and a derived freshwater resident form. We examined the genetic diversity and divergence among 20 estuarine and resident populations across the Chilean distribution of G. maculatus and assessed the extent to which selection is involved in the differentiation among resident populations. We obtained nearly 4,400 SNP markers using a RADcap approach for 224 individuals. As expected, collections from estuarine locations typically consist of diadromous individuals. Diadromous populations are highly differentiated from their resident counterparts by both neutral and putative adaptive markers. While diadromous populations exhibit high gene flow and lack site fidelity, resident populations appear to be the product of different colonization events with relatively low genetic diversity and varying levels of gene flow. In particular, the northernmost resident populations were clearly genetically distinct and reproductively isolated from each other suggesting local adaptation. Our study provides insights into the role of life history differences in the maintenance of genetic diversity and the importance of genetic divergence in species evolution.     

Genetic Variants in SDC3 Gene are Significantly Associated with Growth Traits in Two Chinese Beef Cattle Breeds

Identification of the genes and polymorphisms underlying quantitative traits, and understanding these genes and polymorphisms affect economic growth traits, are important for successful marker-assisted selection and more efficient management strategies in commercial cattle (Bos taurus) population. Syndecan-3 (SDC3), a member of the syndecan family of type I transmembrane heparan sulfate proteoglycans is a novel regulator of feeding behavior and body weight. The aim of this study is to examine the association of the SDC3 polymorphism with growth traits in Chinese Jiaxian and Qinchuan cattle breeds (). Four single nucleotide polymorphisms (SNPs: 1–4) were detected in 555 cows from three Chinese native cattle breeds by means of sequencing pooled DNA samples and polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) methods. We found one SNP (g.28362A > G) in intron and three SNPs (g.30742T > G, g.30821C > T and 33418 A > G) in exons. The statistical analyses indicated that these SNPs of SDC3 gene were associated with bovine body height, body length, chest circumference, and circumference of cannon bone (P < 0.05). The mutant-type variant was superior for growth traits; the heterozygote was associated with higher growth traits compared to wild-type homozygote. Our result confirms the polymorphisms in the SDC3 gene are associated with growth traits that may be used for marker-assisted selection in beef cattle breeding programs.     

Comportements reproducteurs du labre oiseau Gomphosus caeruleus dans un récif de l’île de la Réunion : mode de reproduction,facteurs environnementaux et alternance des stratégies reproductrices

The green birdmouth wrasse Gomphosus caeruleus is present all year round on the coral reefs of Reunion Island (Indian Ocean). A group of individuals was followed on one of these reefs with the objective of studying the reproduction mode of the species, the influence of environmental factors, and social behaviors on the control of reproduction. Our observations revealed that G. caeruleus is, like many Labridae, a protogynous hermaphrodite species, probably diandric, that the reproduction of G. caeruleus is, like in other reef fish species, influenced by the lunar cycle with a peak of reproductive activity during waxing gibbous phase, and that G. caeruleus displays social behavior leading to alternating haremic mating system on a single territory and lek-like mating systems without aggressions between males. These observations enhanced our knowledge of the reproduction of Labridae and reef species.     

Genetic divergence between the South Korean and Mongolian populations of the dung beetle,Gymnopleurus mopsus (Coleoptera: Scarabaeidae) based on mitochondrial cytochrome c oxidase subunit I (COI) gene sequences

The locally extinct dung beetle, Gymnopleurus mopsus Pallas, 1781 (Coleoptera: Scarabaeidae), has not been found in South Korea since the 1970s. This research was conducted to understand the genetic divergence between the South Korean and Mongolian populations of G. mopsus as a part of its reintroduction program in South Korea. The genetic distance and diversity were determined using the mitochondrial cytochrome c oxidase subunit I (COI) gene sequence (658 bp ) corresponding to the DNA barcode region. The mitochondrial COI gene sequences of 64 individuals of G. mopsus collected in South Korea (7 individuals) and Mongolia (57 individuals) showed a relatively high level of genetic diversity (nucleotide diversity, 0.0078 ± 0.0007; Haplotype diversity, 0.965 ± 0.017). The genetic distances between the South Korean and Mongolian populations lay within the intraspecific level and the phylogenetic reconstruction using the neighbor‐joining (NJ) method showed that all individuals belonged to a single clade. This result indicates that the current Mongolian population of G. mopsus is a good candidate source population to restore the locally extinct population of the species in South Korea.     

Physiological and biochemical aspects of tolerance of three grass species to varying Na+/Ca2+ ratios

The effects of decreasing Ca²⁺ concentrations (Na/Ca ratios were 24, 49, 99 and 199) of the saline growth medium (NaCl concentration 200 mM) on three grass speciesCenchrus pennisetiformis Hochst. & Steud,Leptochloa fusca L. Kunth. andPcmicum turgidum Forssk. were assessed after 7 weeks growth in sand culture.L. fusca produced the highest dry biomass of all the species at varying Na/Ca ratios. Number of tillers per plant and number of green leaves per tiller were reduced significantly only inC. pennisetiformis. Leaf water potential ofC. pennisetiformis decreased at all external Na/Ca ratios, whereas inL. fusca it decreased only at an Na/Ca ratio of 99. Leaf osmotic potential ofL. fusca consistently decreased at all Na/Ca ratios, whereas that of the other two species remained unchanged. The shoot and root total sugars of all species remained unaffected at all decreasing Ca²⁺ concentrations. InP. turgidum chlorophyllb and total chlorophyll decreased consistently at all Na/Ca ratios, but inL. fusca they decreased only at the highest Na/Ca ratios. The leaf soluble proteins of all the species remained unaffected at all Na/Ca ratios. The leaf free amino acids decreased significantly inL. fusca with the increase in Na/Ca ratios. The leaf proline content was only decreased inL. fusca at the highest Na/Ca ratio. The significant correlations between the growth of the three grass species and other variables determined in this study were not found.     

Genetic structure and origin of Busseola fusca populations in Cameroon

The cereal stem borer Busseola fusca Fuller (Lepidoptera: Noctuidae) is a species endemic to sub‐Saharan Africa. It is a major pest of maize and cultivated sorghum, the main cereal crops on the African mainland. Previous studies using mitochondrial markers revealed the presence of three clades of haplotypes (W, KI, KII) among B. fusca populations. Previous preliminary studies based on a few B. fusca individuals collected from three localities within the Guineo‐Congolian rain forest in Cameroon demonstrated a matching with clade KII, a fairly surprising result because the putative centre of origin of that clade is located 3 000 km away in East Africa. To check this finding, 120 individuals of B. fusca covering several Cameroonian sites belonging to both Guineo‐Congolian rain forest and Afromontane vegetation mosaics were collected. Comparison of cytochrome b sequences using the same marker revealed low mitochondrial diversity (h = 0.483 ± 0.054, π = 0.073 ± 0.061%). Moreover, molecular diversity in the Guineo‐Congolian rain forest zone was lower than that in Afromontane vegetation, which is therefore thought to be the likely starting point for the colonization of other zones in Cameroon. The study showed a moderate but significant structuring between populations (Φ_ST = 0.034, P<0.001) as well as within and among the two Cameroonian phytogeographical groups considered (Φ_SC = 0.000 and Φ_CT = 0.051, respectively, both P<0.001). Nested clade phylogeographic analysis indicated that all Cameroonian clades with significant geographical associations were interpreted as a phenomenon of contiguous range expansion. All results suggest that the Cameroonian population of B. fusca is relatively recent and originates from the recent geographical expansion of clade KII.     

Delineation of Two Sibling Red Algal Species,Gracilaria Gracilis and Gracilaria Dura (Gracilariales,Rhodophyta), Using Multiple DNA Markers: Resurrection of the Species G. Dura Previously Described in the Northern Atlantic 200 Years Ago1

Molecular markers belonging to the three different genomes, mitochondrial (cox2‐cox3 spacer), plastid (rbcL), and nuclear (internal transcribed spacer [ITS] 2 region), were used to compare samples of the two morphologically related species Gracilaria gracilis (Stackh.) Steentoft, L. M. Irvine et Farnham and G. dura (C. Agardh) J. Agardh collected along Atlantic coasts. In northern Europe, the distinction between these two species is ambiguous, and they are currently recognized under the single name of G. gracilis. The low but congruent patterns of genetic divergence observed for markers of the three genomic compartments highly suggest that these two taxa correspond effectively to two different genetic entities as previously described 200 years ago, based on morphological traits. However, thanks to the combination of different DNA markers, occurrence of “incongruent” cytotypes (i.e., mitotypes of G. dura associated with chlorotypes of G. gracilis) in individuals collected from Brittany, suggests interspecific hybridization between the two sibling species studied.     

Biochemistry and Genetics of Actinomycete Cellulases

Abstract

The order Actinomycetales includes a number of genera that contain species that actively degrade cellulose and these include both mesophilic and facultative thermophilic species. Cellulases produced by strains from two of the genera containing thermophilic organisms have been studied extensively: Microbispora bispora and Thermomonospora fusca. Fractionation of M. bispora cellulases has identified six different enzymes, all of which were purified to near homogeneity and partially characterized. Two of these enzymes appear to be exocellulases and gave synergism with each other and with the endocellulases. The structural genes of five M. bispora cellulases have been cloned and one was sequenced. Fractionation of T. fusca cellulases has identified five different enzymes, all of which were purified to near homogeneity and partially characterized. One of the T. fusca enzymes gives synergism in the hydrolysis of crystalline cellulose with several T. fusca endocellulases and with Trichoderma reesei CBHI but not with T. reesei CBHII. Each T. fusca cellulase contains distinct catalytic and cellulose binding domains. The structural genes of four of the T. fusca endoglucanases have been cloned and sequenced, while three cellulase genes have been cloned from “T. curvata”. The T. fusca cellulase genes are expressed at a low level in Escherichia coli, but at a high level in Streptomyces lividans. Sequence comparisons have shown that there are no significant amino acid homologies between any of the catalytic domains of the four T. fusca cellulases, but each of them shows extensive homology to several other cellulases and fits in one of the five existing cellulase gene families. There have been extensive studies of the regulation of the synthesis of these cellulases and a number of regulatory mutants have been isolated. This work has shown that the different T. fusca cellulases are coordinately regulated over a 100-fold range by two independent controls; induction by cellobiose and repression by any good carbon source.     

MITOCHONDRIAL DNA DIVERSITY IN THE SEA URCHINS STRONGYLOCENTROTUS PURPURATUS AND S. DROEBACHIENSIS

Restriction-fragment analysis was used to measure mitochondrial DNA (mtDNA) variability in 79 individuals of two species of temperate sea urchins. For the purple urchin Strongylocentrotus purpuratus, individuals were collected 1,500 km apart in 1985 and again from the same localities in 1988 (about one urchin generation). Twenty mtDNA genotypes belonging to four clades were found among 38 individuals. All four clades were found in both localities and in both years. Genetic structure was further tested by calculating the degree of interdeme genetic variation (G_ST) and comparing this value to the G_ST's from randomly shuffled data. No geographic structure was found. For S. droebachiensis, only six mtDNA genotypes were found among 41 individuals collected from the Pacific and Atlantic oceans. More than 80% of the individuals belonged to two genotypes. The genotype that dominated collections in the Pacific also occurred in the Atlantic; however, a common Atlantic genotype was never found in the Pacific. These two genotypes were identical at 64 of 65 restriction sites, and were only 0.2% divergent from each other. G_ST analysis confirmed that there were significant genetic differences between Atlantic and Pacific populations. The small divergence between genotypes suggests recent, but not continuous, migration. These marine species show smaller genotypic differences than terrestrial species over similar spatial and temporal scales. Both recruitment of adults from planktonic larval pools and the spread of sibling larvae over large distances from parents probably act as buffers to genetic differences in species with planktonic life-history phases.     

Characterization of some members of the genusThermomonospora

Twenty strains ofThermomonospora, isolated from the environments of patients with hypersensitivity pneumonitis or received from culture collections or other workers, were studied for their detailed morphological, physiological, and immunological characteristics. The species studied includedThermomonospora fusca, T. alba, T. curvata, T. mesophilia, andT. mesouviformis. The results indicate that several species can be differentiated by various criteria studied; however, two species,T. fusca andT. alba, could not be separated from one another by any of the tests or methods used in the study.     

What is the taxonomic status of East Asian otter species based on molecular evidence?: focus on the position of the Japanese otter holotype specimen from museum

The Japanese otter (Lutra nippon), once inhabited in most islands of Japan, is now considered as an extinct species. Although the Japanese otter is regarded as a distinct species from the Eurasian otter (L. lutra), its phylogeny and taxonomic status are based on limited information on morphological and genetic data, and thus further clarification is required. Here, we assessed the phylogenetic relationship among the genus Lutra and taxonomic status of L. nippon by using the complete sequences of cytochrome b gene of its holotype. The present phylogenic trees supported that the genus Lutra specimens largely formed monophyletic group, with L. sumatrana as a basal to other Lutra species. Within Lutra species, L. nippon was distantly related with L. lutra. The European otter population of L. l. lutra were clustered together with its subspecies, L. l. chinensis rather than the same subspecies, Korean otter population. The discrepancy between the genetic data and traditional taxonomy justifies the necessity of reexamination of the current subspecific classification system of Eurasian otters. Level of genetic divergence between the holotype of L. nippon and L. lutra was two to three-fold lower than those among the other sister species of the Lutrinae. Based on the level of divergence between the L. nippon and L. lutra, and insufficient evidence of morphological difference between them, it is suggested that designation of Japanese otter as a separate species from L. lutra will be reconsidered.     

Spawning seasonality and body sizes at sexual maturity in the bluespine unicornfish,Naso unicornis (Acanthuridae)

We herein evaluate several reproductive metrics of Hawaiian Archipelagic populations of the bluespine unicornfish (Naso unicornis), an economically and ecologically important, broadly distributed tropical Pacific reef fish, based on multi-year, fishery-dependent and fishery-independent collections. Sex-specific spawning seasonality was characterized for fish collected mostly from Oahu (Main Hawaiian Islands, MHI) using a gonadosomatic index. Histological slides preparations were used to score gonad developmental phase and to classify individuals of either sex as immature or mature. Sex-specific median body lengths at maturity (L₅₀) were estimated by logistic fits of proportion mature versus length class. Spawning was highly seasonal in Hawaii, with a single brief (May–June) peak spawning period. Proportionate gonad-to-body weight values were relatively low, averaging only about 0.1 % and 0.6 % across all months of year and 0.16 % and 1.03 % during May–June for males and females, respectively. Median lengths at sexual maturity differed between the sexes. L₅₀ values for fish collected throughout all months of year were 30.1 ± 0.5 (standard error) cm Fork Length (FL) for males and 35.5 ± 0.7 cm FL for females. Spawning seasonality and L₅₀ estimates for bluespine unicornfish in Hawaii suggest that the species spawns several months earlier in the calendar year and matures at larger body lengths in Hawaii versus Guam, the Northern Mariana Islands, and Pohnpei in the Federated States of Micronesia. Estimated lengths at sexual maturity are compared to the minimum length (14 inches or 35.6 cm FL) mandated for this species in Hawaii: median size at maturity occurs at a length appreciably less than (males) or approximately equal to (females) minimum legal size. A likely disproportionately large contribution of old females to population replenishment is discussed relative to the minimum size limit.     

A brief evolutionary excursion comes to an end: the genetic relationship of British species of Gentianella sect. Gentianella (Gentianaceae)

 There is much taxonomic confusion in the genus Gentianella section Gentianella, five species of which are found in Britain. Gentianella anglica is a British endemic restricted in its distribution to the chalk downland of southern England. It is considered to be threatened because of habitat loss, and due to hybridisation with the closely related, widely distributed G. amarella. The Red Data Book species, G. uliginosa, shares morphological similarities with the other two species but has a very restricted distribution. Individual plants from populations across the range of these three species were analysed using AFLPs and universal cpSSRs to determine the degree of genetic variability within and between them, and to look for evidence of hybridisation. Samples of the two other Gentianella section Gentianella species found in Britain, G. campestris and G. germanica, were also included in the study. The analysis of chloroplast SSRs was not informative for G. anglica, G. amarella and G. uliginosa, while G. campestris and G. germanica differed from each other and the other three species at a single locus. Principal co-ordinate analysis of the AFLP data revealed only three distinct groups: one group contained G. campestris samples, another contained all samples of G. germanica, and a third contained all individuals from the other three species. In mixed populations of G. anglica and G. amarella, individuals of the two species were genetically more similar to each other than they were to individuals of the same species from other populations. It is proposed that G. anglica may be an early flowering form of G. amarella that has been created and maintained as a consequence of former grassland management practices. Received May 20, 2002; accepted October 28, 2002 Published online: March 31, 2003