Genetic rescue of an inbred captive population of the critically endangered Puerto Rican crested toad (<Emphasis Type=Italic>Peltophryne lemur</Emphasis>) by mixing lineages

The Puerto Rican crested toad (Peltophryne lemur) is currently composed of a single wild population on the south coast of Puerto Rico and two captive populations founded by animals from the northern and southern coasts. The main factors contributing to its decline are habitat loss, inundation of breeding ponds during storms, and impacts of invasive species. Recovery efforts have been extensive, involving captive breeding and reintroductions, habitat restoration, construction of breeding ponds, and public education. To guide future conservation efforts, genetic variation and differentiation were assessed for the two captive colonies and the remaining wild population using the mitochondrial control region and six novel microsatellite loci. Only two moderately divergent mitochondrial haplotypes were found, with one fixed in each of the southern and northern lineages. Moderate genetic variation exists for microsatellite loci in all three groups. The captive southern population has not diverged substantially from the wild population at microsatellite loci (F _ST = 0.03), whereas there is little allelic overlap between the northern and southern lineages at five of six loci (F _ST > 0.3). Despite this differentiation, they are no more divergent than many populations of other amphibian species. As the northern breeding colony may not remain viable due to its small size and inbred nature, it is recommended that a third breeding colony be established in which northern and southern individuals are combined. This will preserve any northern adaptive traits that may exist, and provide animals for release in the event that the pure northern lineage becomes extirpated.     

A revision of the Puerto Rican species of lepanthes (Orchidaceae)

Six species of the orchid speciesLepanthes are described as new. A seventh species,L. sanguined, previously known only from Jamaica, is reported from Puerto Rico. The current misspelling ofL. selenitepala, the only species of the genus previously reported from Puerto Rico, is corrected. A key to the eight Puerto Rican species ofLepanthes is presented, and the value of several interesting taxonomic characters is discussed. The possibility of apogamy in this genus is raised, and detailed biosystematic investigations are indicated as necessary for a complete understanding of the group.     

Reproduction of the mongoose lemur (Lemur mongoz) in captivity

Responses to questionnaires sent to 20 institutions holding Lemur mongoz did not reveal which aspects of management or husbandry could account for reproductive failure in the captive population, but allowed some qualitative comparisons with data compiled for captive and wild animals. In general, reproduction has occurred initially among wild-caught specimens before tapering off, and rarely occurs in the captive F₁ generation. Data compiled by the International Species Inventory System and the International Zoo Yearbook revealed an aging captive population with no recent reproduction. No aspect of group composition, activity patterns, seasonal light regime, reproductive cycles, or diet could be linked to the lack of reproduction; and among lemurs subjected to the same conditions, some were known to reproduce while others did not. Lack of knowledge about this species and the threat of extinction for both captive and wild populations make an investigation of reproductive biology imperative. Recommendations for a research program are given.     

Biology of Cotesia ( = Apanteles) telengai (Hymenoptera: Braconidae) on its natural host Agrotis segetum (Lepidoptera: Noctuidae)

The host suitability of Agrotis segetum Denis & Schiff., A. ipsilon Hufn., Spodoptera littoralis Boisd, S. exigua Hub., Mythimna loreyi Duponchel and Mamestra oleracea L. for the gregarious braconid Cotesia ( = Apanteles) telengai Tobias was determined under laboratory conditions. The parasitoid only completed its development in larvae of A. segetum. The percentage of successfully parasitized larvae and the mean duration of C. telengai egg‐larval period were inversely related to the age of the host or host instar at parasitization. The mean number of parasitoids which emerged per parasitized larva was positively correlated with the larval age. The sex ratio was consistently high (ca. eight males to one female), independent of the host instar parasitized, as compared to 1:1 as observed frequently in field populations of this wasp. The females of C. telengai were active and produced offspring at temperatures of 15, 20, 25 and 30° C. However, the mean percentage of parasitized larvae increased from 13.1 to 72% and the mean progeny per parasitoid female increased from 14.7 to 129.4 parasitoids, both significant, when the experimental temperature was raised from 15 to 30°C, while their mean development time decreased from 75.5 to 19.2 days. At 25°C, the virgin and mated females continued oviposition until days 16 and 17, with a lifetime total of progeny of 397.6 (SD ±224.7) and 611.1 (SD± 128.8) parasitoids respectively, reaching a maximum of 64.3 and 99.2 on day 2 respectively.     

Relative growth and morphological sexual maturity of the deep-water velvet shrimp Metapenaeopsis sibogae (Crustacea,Decapoda, Penaeidae)

Metapenaeopsis sibogae inhabits the South Pacific and Southeast Asia and is an emerging fisheries resource. However, studies on the population biology of M. sibogae are scant, and their morphometric relationships have not been examined. Thus, we studied the relative growth of M. sibogae, hypothesizing that its morphological sexual maturity can be estimated based on abrupt shifts in allometry. The relationships of body length (BL) and body weight (BW) with carapace length (CL) were determined by the least squares method. Data for each sex were repeatedly partitioned into two size-delimited subsets (early and late phases), considering a CL value as a hypothesized transition point. Analysis of the sum of squared residuals indicated that two separate linear BL/CL models fit the data better than a single linear model showing clear transition points in both males (13.2 mm CL) and females (15.0 mm CL). The changes in allometry in the BL/CL relationships between early- and late-phased males and females were indicated by a 20.5 and 21.5% decrease in the slope, respectively. These transition points could be associated with sexual maturity. The growth rate of BW vs. CL slowed significantly after morphological sexual maturity was reached in both sexes, demonstrating the existence of dimorphic growth.     

Synchronized maturation and breeding in natural populations ofXiphophorus variatus (Poeciliidae)

Synopsis Reproductive events tend to be synchronized in natural populations ofXiphophorus variatus. Males physically resembling one another tend to mature at the same rate and time. This coordinate development has also been seen in the laboratory. We hypothesize that juveniles resembling each other experience fewer aggressive responses from males than do juveniles without look-alikes, because of habituation of aggression. This would decrease social inhibition and permit their synchronous development.Females have an ovarian cycle. In the laboratory, crowding stress causes a suspension of breeding while a return to uncrowded conditions permits its resumption. Females released simultaneously from crowding tend to be synchronized in subsequent broods, although the synchrony deteriorates with time. Synchronizing events are shown to occur in natural populations.The consequences of reproductive synchrony in males and females are briefly discussed.     

Advertisement call variation and individual acoustic distinctiveness in the explosive breeding toad <Emphasis Type="Italic">Peltophryne cataulaciceps</Emphasis> (Anura: Bufonidae)

In this contribution, we offer new information about the advertisement call of Peltophryne cataulaciceps, an endemic toad species from Cuba and the smallest bufonid from the West Indies. We measured seven acoustic properties from 17 males and analyzed the variability at the within-individual and between-individual levels, using coefficients of variation, type II ANOVAs, and multivariate analysis. Dominant frequency was distinctly less variable within individuals than the rest of the acoustic properties; call rise time showed the highest variability. Variability between individuals was higher for pulse rate, call duration, and dominant frequency, and the CVb/CVw ratios showed that these acoustic properties are more reliable for individual distinctiveness. Discriminant function analyses assigned 54.1% of the calls to the correct individual, and this classification success increased when smaller groups of individuals were considered in the analysis. Results are compared with studies addressing individual acoustic distinctiveness in anurans. We support that the patterns of advertisement call variation within and among co-occurring males differ among explosive and prolonged breeding species/populations, but additional case studies including other explosive breeding species are needed.     

Premetamorphic bonefish (Albula sp.) leptocephali from the Gulf of California with comments on life history

Synopsis Ten early premetamorphic bonefish (Albula sp.) leptocephali were collected in MOCNESS plankton tows in the Guaymas Basin area of the Gulf of California from 27 July–1 August, 1985. Initial captures of five larvae showed that these were found only in surface waters (0–100 m) at temperatures of 15–29° C. A shallow tow made from 200 m to the surface resulted in the capture of five additional larvae that were distributed in the upper 50 m of the water column at temperatures of 21–29° C. Both pre-flexion larvae (<17.0 mm notochord length, NL) and larvae with flexed notochords were captured. The size range was from 12.0 mm NL to 27.0 mm standard length. Drawings of representative larvae are given. This is apparently the first report of premetamorphic bonefish larvae for the Gulf, although metamorphic larvae have been known to be abundant in coastal areas of this region for almost 100 years. Distribution records for metamorphic larvae are reviewed. This, together with observations on seasonal distribution of ripe adults in coastal waters near Guaymas, Sonora, Mexico, has allowed us to speculate on various aspects of life history. Our data suggest that spawning occurs during late spring and summer and that early development takes place offshore. The premetamorphic interval is postulated to last approximately 6–7 months. Larvae then return to coastal areas during the winter and spring to complete metamorphosis.     

Observations on natural breeding and larval development of the common mud-eel Amphipnous cuchia (Ham.)

Amphipnous cuchia is a rare fish in India with a spawning period confined down to peak summer. The fish lays its eggs in especially prepared nest-holes and keeps a guard on the developing young ones. The yolk reserve persists till about 22 to 24 days of development. Larvae respond to direct feeding even before yolk-absorption. The young ones feed actively on chironomus larvae. Surface breaking habit for aerial respiration apparently commences around 15th–16th day of larval life. Adult characters are almost attained in about a month's time.     

The effects of temperature and food on naupliar development,growth and metamorphosis in three species of Boeckella (Copepoda:Calanoida)

Three species of Boeckella (B. triarticulata, B. dilatata and B. hamata) were reared from hatching to copepodite I (CI) at three naturally fluctuating food levels and three temperatures in a 3 × 3 × 3 factorial design. Development times, lengths and mortality were measured for each species in nine treatments. Temperature had the major effect on development times but food level had the major effect on CI lengths. Mortality varied interspecifically with treatment. The combined effect of temperature and food on development times and lengths was species-specific. There were trade-offs between development time and growth to meet constraints imposed by naupliar metamorphosis. The three species varied in the timing of metamorphosis to CI. B. triarticulata nauplii were age determined, B. dilatata nauplii were size determined and B. hamata nauplii were flexibly age and size determined depending on treatment. Differences in life history parameters and the timing of naupliar metamorphosis are discussed in relation to the distributions of the species in ponds (B. triarticulata), glacial lakes (B. dilatata) and coastal lakes (B. hamata) in the South Island of New Zealand.     

Growth forms of Leymus chinesis (Poaceae) at the different developmental stages of the natural population

The manner in which the density of Leymus chinensis increases from a single plant to a dominant population can be understood by tracing the development of a population from early to late stages. Parent shoot density, above‐ground dry weight, spike density, heading rate and spike dry weight, density of spreading shoots (buds/daughter shoots in apical/axillary rhizomes) and clumping shoots (buds/daughter shoots in axillary parent shoots), and young rhizome length and weight were investigated in the same quadrats for a low density/early stage (LE) population and a high density/late stage (HL) population. Clonal growth (buds/daughter shoots formation) and sexual reproduction (spikes formation) increased while rhizome storage (young rhizome weight) decreased during the transition from LE to HL. In a LE population an outward occupation strategy was employed, with a high proportion of spreading shoots. As the population density gradually increased until HL, an inward consolidation strategy increasing shoot amount in previously occupied areas, was adopted. This was characterized by a high proportion of clumping shoots. Interestingly, the trade‐off between spreading and clumping shoots can be adjusted by the duration of young rhizome elongation during a growth season. In other words, compared with a HL population, a LE population shortened the duration of young rhizome elongation during the growth season, which resulted in more time for the production of axillary spreading shoots along the rhizomes, and high amounts and proportions of total spreading shoots. The special growth patterns, that is, trade‐offs among growth forms, allow L. chinensis to establish dominant populations throughout the eastern Eurasian Steppe.     

Polymorphic microsatellite loci for the Puerto Rican crested anole (<Emphasis Type="Italic">Anolis cristatellus</Emphasis>) and their amplification in related Puerto Rican species

We isolate six highly polymorphic microsatellite loci for the Puerto Rican crested anole (Anolis cristatellus) from a genomic library enriched for CA repeats. The number of alleles per locus ranged from 14 to 19, with levels of observed heterozygosity ranging from 0.60 to 0.73. Most of these loci were successfully cross-amplified in other members of the cristatellus species group (A. evermanni, A. gundlachi, A. krugi, A. stratulus), but levels of polymorphism were lower.     

Leaf growth and demography of the rheophytic fern Thelypteris angustifolia (Willdenow) Proctor in a Puerto Rican rainforest

Morphological and temporal aspects of the growth of leaves of Thelypteris angustifolia (Willdenow) Proctor are under study along a 400-m section of the Sonadora River at the El Verde Field Station in the Luquillo Experimental Forest of Puerto Rico. Emergence, expansion and growth of leaves of 149 sporophytes have been observed approximately mid-month every January, May and September since September 1991. Results of the first four years of this long-term study of T. angustifolia are reported here. Although they are land plants, sporophytes of T. angustifolia are rheophytic, subject to intermittent flooding and submerged approximately 7% of the time. The pinnate leaves of T. angustifolia exhibit sterile-fertile leaf dimorphy. Only 7.6% of the leaves in the the sample were fertile. The petiole of a fertile leaf was 41% longer than that of a sterile leaf while leaf blades were the same length. Leaves expanded at a mean rate of 1.7 cm per day, maturing in 29.7 days. Mean leaf life span was 10.8 months with a maximum of 26 months. Sterile leaf longevity (11.0 months) was longer than that of the fertile leaf (9.6 months). Leaves were produced at a mean rate of 4.7 leaves per plant per year. Leaf damage occurred on 38% of the leaves observed. Net leaf counts for individual sporophytes ranged from one to eight with a mean of 3.0 leaves per plant. Fertile plants had higher mean leaf counts (4.1) than plants without fertile leaves (2.8). Leaf production, although possibly triggered by increasing daylength, also paralleled seasonal increases in rainfall during the wetter mid-May/September months. Increased leaf mortality occurred during the drier mid-January/May period.