Population dynamics, reproduction, and diet of the lesser long-nosed bat (Leptonycteris curasoae) in Jalisco, Mexico: implications for conservation

We estimate fluctuations in population size and sex ratio, documentbreeding behavior and reproduction, and determine the diet of a population ofthe lesser long-nosed bat, Leptonycteris curasoae, in anisland cave in Chamela Bay, Jalisco, Mexico, with monthly sampling during anannual cycle (October 1999–October 2000). Based on the area of thecave's ceiling and wall covered with L. curasoae inrelation to the potential roost area without them, in 1999 the abundanceincreased from 80% in October to 100% in November and December. In 2000 thepopulation decreased to 80% in January, 50% in February, 30% in March, 20% inApril, 10% in May, 5% in June and July, and less than 1% in August. Thepopulation rapidly increased to 60% in September and to 80% in October.Throughout the year there were significantly more males than females; however,there was significant heterogeneity over months. In September–Novemberthere were more females, but in December–August there were more malespresent. The majority of pregnant and lactating females were observed fromDecember to March and in July, while males were reproductive fromSeptember–January and in May–June. Breeding activity was observed inthe cave in November–December. Twenty-six species of plants were consumedduring the year, based on pollen identification from fecal samples. Bombacaceousspecies were the most important component of the diet from January to May andCactaceae were most important in June–September. Peak abundance and reproductive activitycoincided with peak flower resource availability, which occurred between Octoberand January and in June–July. The year-round presence and reproductiveactivity of L. curasoae at this site throughout the yeardemonstrate that many individuals are annual residents in this area and indicatethe importance of this roosting site. In order to develop a successfulconservation program for L. curasoae, in addition toprotecting migratory corridors and northern maternity roosts, it is equallyimportant to identify and protect areas that function as breeding colonies andyear-round sanctuaries for resident populations in the south.     

Annual reproductive cycle,spawning periodicity and sexual maturity of false scad Caranx rhonchus (Geoffroy Saint‐Hilaire, 1817) (Pisces,Carangidae) from the South‐Eastern Mediterranean (Gulf of Gabès,Tunisia)

The reproductive biology of Caranx rhonchus (Geoffroy Saint‐Hilaire, 1817) (Pisces, Carangidae) was studied in the Gulf of Gabès (Mediterranean Sea) from June 2004 to May 2006. Of 1313 individuals examined, 668 were females (50.9%) and 645 were males (49.1%). The overall sex ratio did not deviate significantly in favour of females (♀ : ♂ = 1.04 : 1). Monthly changes in the Gonado–Somatic Index (GSI) showed a rapid increase from May to June and an extended very high level from June to September (4.43–3.47% for females and 3.35–2.61% for males), before declining sharply in October (down to 2.02% for females and 0.57% for males). The gametogenesis activity began with a pre‐maturation phase from March to May, followed by a ripe‐spawning phase from June to September. From the last days of July to the end of October, the gonads were in the spent and post‐spawning stages. From November to early May, gonads were in the resting stages. The size at which 50% of the population reached sexual maturity was not significantly different between males and females :  males attained sexual maturity at fork length FL₅₀ = 161.20 ± 0.37 mm (n = 262), whereas females attained maturity at FL₅₀ = 160.70 ± 0.23 mm (n = 296). The age of maturity for both sexes occurred at 2.1 years.     

Stage-specific population dynamics of cottony cushion scale,Icerya purchasi (Hemiptera: Monophlebidae), in citrus orchards in Jeju,Korea

The cottony cushion scale, Icerya purchasi Maskell (Hemiptera: Monophlebidae), is a polyphagous, cosmopolitan and destructive pest of citrus. This study was conducted to obtain the stage-specific phenology of I. purchasi for seasonal management strategies in the field. Movement of crawlers (hatched nymphs) in egg sacs of overwintered females started in late May, peaked in early to mid-June, and was completed by late June. Generally, the 1st generation occurred from late May until late September and the overlapping second generation occurred from early September. The 1st nymphs in the 1st generation peaked in mid June. The 2nd nymphs showed peak activity in late July. The 3rd nymphs showed peak population in early September. The 1st generation adults peaked in mid September. In the 2nd generation, the 1st nymphs peaked in early October, the 2nd nymphs showed peak activity in late October, and the 3rd nymphs reached a plateau after mid October. The 2nd generation adults occurred from late October. Consequently, two life cycles were competed in the Jeju area. The average fertilities of I. purchasi were 623 and 247 crawlers per female in overwintered and summer generations, respectively. An average of 20.7% of all citrus orchards was infested with I. purchasi, with a mean of 3.9% infested trees in Jeju. These results should be useful in establishing management strategies for I. purchasi in citrus orchards.     

Phenotypic plasticity in the spawning traits of bigheaded carp (Hypophthalmichthys spp.) in novel ecosystems

1. Bigheaded carp, including both silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp, are successful invasive fishes that threaten global freshwater biodiversity. High phenotypic plasticity probably contributes to their success in novel ecosystems, although evidence of plasticity in several spawning traits has hitherto been largely anecdotal or speculative. 2. We collected drifting eggs from a Midwestern U.S.A. river from June to September 2011 and from April to June 2012 to investigate the spawning traits of bigheaded carp in novel ecosystems. 3. Unlike reports from the native range, the presence of drifting bigheaded carp eggs was not related to changes in hydrological regime or mean daily water temperature. Bigheaded carp also exhibited protracted spawning, since we found drifting eggs throughout the summer and as late as 1 September 2011. Finally, we detected bigheaded carp eggs in a river reach where the channel is c. 30 m wide with a catchment area of 4579 km², the smallest stream in which spawning has yet been documented. 4. Taken with previous observations of spawning traits that depart from those observed within the native ranges of both bighead and silver carp, our findings provide direct evidence that bigheaded carp exhibit plastic spawning traits in novel ecosystems that may facilitate invasion and establishment in a wider range of river conditions than previously envisaged.     

Wing morphology variations in a natural population of Phlebotomus tobbi Adler and Theodor 1930

Cutaneous leishmaniasis (CL) is highly endemic in the Cukurova region, located on the crossroads of main refugee routes from the Middle East to Europe on the eastern Mediterranean part of Turkey. Our purpose was to investigate the phenotypic variation of Phlebotomus tobbi, the known vector of CL in the region, during one active season. Sand flies and microclimatic data were collected monthly from May to October, 2011, from five locations in six villages in the study area. A geometric morphometric approach was used to investigate wing morphology. Shape analyses revealed that males collected in May and June comprised one group, while specimens collected in August, September, and October formed a second group. Specimens from July were found to be distributed within these two groups. A similar distribution pattern was observed for females, but specimens from October were represented as the third district group. Significant size variation was detected for both sexes between months. Wing size and temperature were negatively correlated for females, but there was no temperature effect for males. Wing size of both sexes was increased in correlation to increasing relative humidity. Males were found to have smaller wings with increasing population density.     

Gonad development and sperm motility of the diving beetle Cybister brevis Aubé, 1838 (Coleoptera: Dytiscidae) in response to seasonal changes in Japan

Gonad maturation in wild Cybister brevis Aubé, 1838 from Japan was investigated to determine the physiological mating season. Breeding experiments showed that hatching occurred from May to September, and the peak was observed in July. The gonadosomatic index (GSI) in collected females (ovary development) showed the highest value in May. The GSIs were low in other seasons. On the other hand, the GSIs in collected males (testes and accessory glands) remained at constant values during the experimental period. Interestingly, high sperm motility was exhibited in May and September, whereas it was low in December and March. This indicates the maturation difference between females and males. Females mature only at the beginning of the breeding season (May), but males do so from May to September. This result suggests that males have a wide-ranging maturation period and earlier sexual maturation than females, ensuring a successful fertilization.     

Reproductive cycle and fecundity of the bonnethead Sphyrna tiburo L. from the northwest Atlantic Ocean

The present study examined temporal changes in plasma sex hormone concentrations and the morphology and histology of reproductive organs in mature northwest Atlantic (NWA) bonnetheads Sphyrna tiburo L. to characterize reproductive cycle, breeding periodicity and fertility in this still poorly studied population. Progressive increases in testis width, epididymis head width, plasma testosterone (T) concentrations, and occurrence of mature spermatozoa were observed in male S. tiburo from June to September, demonstrating that spermatogenesis occurs during the summer. Nonetheless, increases in maximum follicle diameter, oviducal gland width, plasma 17β-estradiol and T concentrations, and occurrence of vitellogenic follicles were not observed in mature females until between October and April, demonstrating non-synchronous patterns of gametogenesis in males and females. Fresh copulatory wounds were observed in females collected during late September along with histological evidence for sperm presence in the oviducal gland between September and April, confirming a 6- to 7 month period of female sperm storage. Ovulation occurred between mid-April and early May in concert with increases in female plasma progesterone concentrations. Gestation occurred during a 4.5- to 5 month period between May and early September, and 97% of mature females collected during this period were gravid, indicating a highly synchronized, annual reproductive periodicity. Brood size was significantly correlated with maternal size and ranged from 1 to 13 pups with a mean ± S.D. of 8.1 ± 2.2, which was significantly lower than reported in Gulf of Mexico (GOM) populations. The occurrence of non-fertile offspring was observed in 17% of broods with a range of 1–7 non-fertile eggs present in individual females. Thus, as previously reported in GOM S. tiburo, this unusual form of infertility also appears to be prevalent in the NWA population and requires further study. This study has demonstrated meaningful differences in reproductive biology of these populations, emphasizing the need for region-specific approaches for population management.     

Ecological studies on the community of drifting seaweeds in the south-eastern coastal waters of Izu Peninsula, central Japan. I: Seasonal changes of plants in species composition, appearance, number of species and size

Seasonal patterns of drifting seaweeds in the southeastern coastal waters of Izu Peninsula of central Japan were examined by sampling 966 patches from spring to autumn 1991–1993. In total, 57 plant species appeared, including 10 epiphytic algal species. Monthly totals of the number of species, excluding epiphytic aigae, were highest in May (33) and August (27), though 19–21 species of sargassaceous algae were found from May to August, The number of species, excluding epiphytic algae, in one patch of drifting seaweeds was 1 to 11 (x?= 2.93 ± 2.06) with high richness in May a result of almost entirely sargassaceous species. The wet weight of each patch and maximum stipe length of plants varied from 5 to 6970 g and from 20 to 840 cm (x?= 536.1 ± 782,3 g and 110.6 ± 76.8 cm), respectively, with highs in April and May. Out of 18 species common to all years, 10 species dominated the top or second rank in monthly pooled frequency of appearance. Seasonal changes of these 10 major species were examined, Sargassum horneri (Turner) C. Agardh and Hizikia fusiformis (Harvey) Okamura were abundant in April, but were replaced partly by Sargassum muticum (Yendo) Fensholt in May and largely by Sargassum yamamotoi Yoshida in June. In July, Sargassum nipponicum Yendo and Sargassum piluliferum (Turner) C. Agardh dominated. Subsequently, the major species shifted to Sargassum ringgoldianum Harvey and S. yamamotoi in August, Sargassum micracanthum (Kützing) Endlicher, Sargassum macrocarpum C. Agardh and Zostera marina Linnaeus in September, and S. ringgoldianum and S. micracanthum in October. However, the occurrence of S. yamamotoi, S. nipponicum and S. piluliferum in June or July were particularly heterogeneous compared with other areas of Japan. Dendrogram analysis was done based on frequency of appearance. Pooled monthly samples were divided into three groups characterized from the dominant species, degree of domination, weight, length and number of species of drifting seaweeds as well as the degree of diversity or evenness in appearance. This characterization indicated that the diversity and abundance of drifting seaweeds were higher from April to June than in later months.     

Life cycle of a small endemic goby Economidichthys pygmaeus (Family: Gobiidae) in Lake Pamvotis,northwestern Greece

The life history tactics of the small endemic freshwater goby Economidichhtys pygmaeus were examined in a Mediterranean shallow lake located in the northwestern part of Greece (Lake Pamvotis). The purpose of the study was to define the population structure, growth, length at sexual maturity, sex ratio, annual cycle of gonad development, spawning characteristics and fecundity. Fish samples were collected using a hand net from October 2006 to September 2007. The fish grew rapidly in summer after hatching, matured after their first winter, and bred from February to June. The length frequency distribution indicated the appearance of two cohorts per year. Juveniles occurred in samples from April to September. Maturity length (ML₅₀) of males and females were estimated to be 23.54 and 23.28 mm TL, respectively. Sexual dimorphism related to the male caudal fin was observed and males grew to greater lengths than females. The overall ratio of males to females was 1:1.35. Spawning was from February to June. Ripe females appeared to be multiple spawners, with oocytes at different stages of development. Size of oocytes changed during maturation and increased in diameter from about 0.125 to more than 0.9 mm. Absolute fecundity was positively related to TL and TW and varied between 59 and 309 eggs. After reproduction, the number of parental individuals decreased.     

Reproductive biology of Sarotherodon mossambicus (Cichlidae) in Plover Cove Reservoir,Hong Kong

Synopsis A 16-month study (August 1972 to November 1973) of Sarotherodon mossambicus in the Plover Cove Reservoir, Hong Kong revealed a sex ratio of 1:1 for small fish (below 19 cm standard length), but above this length males predominated in the population. Monthly sex composition also showed this approximately 1:1 ratio except during the months of August and September, when again males predominated. Males and females reached M₅₀ at an average length of 17.8 cm and 16.2 cm respectively. Maturity and gonosomatic index studies showed that spawning occurred from May to October with peaks in June and August, and there were at least two spawnings each year. The relationship between fecundity and standard length of females collected during both spawnings was computed to be F = 118.49L–1150.91.     

Growth and reproduction of Chelidonichthys lucerna (Linnaeus) (Pisces: Triglidae) in the Gulf of Gabès,Tunisia

Growth and reproduction of Chelidonichthys lucerna is reported from Tunisian waters. A total of 286 specimens was collected from landings of bottom trawlers between January 2003 and November 2004. The total length ranged from 16 to 36 cm in females and from 17 to 26 cm in males. Marginal increment analysis of otoliths showed that the translucent zone was laid from October to May and the opaque zone laid from June to September. Females were from 0.5 to 9 years and males from 1 to 7 years old. Growth parameters of the von Bertalanffy growth function were TL_∞ = 40.26; K = 0.06 and t₀ = ?3.03 in females and TL_∞ = 46.16; K = 0.059 and t₀ = ?1.32 in males. The coefficient of the allometric length–weight relationships differed significantly by sex. Females with mature gonads were observed between October and May, with peaks in January and February. Length at which 50% of specimens were mature was 21.6 cm TL (estimated age about 3 years) in females and 19.2 cm TL (estimated age about 1.5 years) in males.     

The reproductive cycle of the Nile crocodile (Crocodylus nilotkus)

The reproductive cycle of the Nile crocodile ( Crocodylus niloticus ) was studied in Zimbabwe. Females attained sexual maturity after they had reached a total length of about 262 to 287 cm and males, 270 to 295 cm. Some adult females did not reproduce every year. Follicle growth and vitellogenesis occurred from April to mid August during the dry winter. During this time reproductive females had elevated levels of plasma oestradiol-17β, testosterone, calcium and magnesium, but lowered levels of iron. The measuring of plasma calcium was an 'early pregnancy' test, reliable up to four months before nesting. Elevated levels of plasma testosterone in reproductive females corresponded to the time of courtship and mating. Ovulation occurred during the latter half of August. Males had viable sperm from mid May to mid September, during the winter. Courtship and mating occurred from late June to mid August, when crocodiles were confined to pools. Females nested on the higher sand ridges in the dry river bed from early September to early October, and eggs hatched during December.     

Life history of Corophium curvispinum G. O. Sars (Crustacea,Amphipoda) living on macrophytes in Lake Balaton

Samples of the amphipod Corophium curvispinum were collected from Myriophyllum spicatum twice a month during the vegetation period. The animals were sexed, their length measured and the eggs of females were counted. Length frequency histograms served to follow the life history of C. curvispinum.Reproduction lasts from May to October. The animals born in May–June reproduce in the same year while the summer-autumn generation reproduces the following year. The life span is about 1 year. The highest fecundity was found in June, the lowest in October.     

Population parameters and reproductive biology of the Iberian hareLepus granatensis in southern Iberia

To analyse the population structure and reproductive biology of the Iberian hareLepus granatensis Rosenhauer, 1856, 498 hares (264 males and 234 females) were collected in monthly samples from October 1998 to September 1999. Females reached larger sizes than males, with approximately 400 g difference in body mass on reaching sexual maturity. The total sex ratio was 1∶1, with a bias in favour of males in winter. Sexually active males and females appeared in every month but August, when no sexually active female was found. Births occurred in every month and were more frequent between March and July. Seasonal variation in kidney fat index (KFI) followed a similar pattern in males and females, with an increase in mid-autumn and a decline at the end of winter. Reproductive activity appeared in every month, with a maximum from February to June. Reproductively hyperactive females (simultaneously pregnant and nursing) appeared in every month except in January, with a first peak in March and a second lower peak in May–June. Litter size fluctuated between 1 and 7 leverets. The most frequent gestations involved 1 or 2 foetuses. The mean annual litter size was 2.08 and the average number of litters per productive female per year was estimated to be 3.48. The maximum productivity was recorded between March and May. The total annual production of young per adult female was estimated to be 7.21. The minimum annual survival rate of young was 27.91%. On the basis of these results we propose to maintain the limit of the hunting period between October and December. We discuss the relationship between the low young/adult ratio obtained and the hunting method used.     

Mating behaviour and light conditions cause seasonal changes in the dispersal pattern of the satyrine butterfly Lethe diana

1. The spatial arrangement of resources and climatically favourable sites affects the dispersal pattern of butterflies. 2. The microdistribution of the satyrine butterfly Lethe diana changes seasonally, meaning that the relative spatial arrangement of resources also changes seasonally. The seasonal change in the dispersal pattern of this butterfly was studied. 3. Males of the May–June generation tended to stay in a restricted habitat patch while females of the same generation did not. A number of the May–June generation males became resident at prime forest edge sites, where a territorial behaviour that was rarely seen in other generations was prevalent. Females of the May–June generation moved to these territorial sites for mating but left after copulation to avoid male harassment; their residency was therefore weak. 4. In both sexes, the July–August generation tended to be more mobile than the September–October generation. This was because the July–August generation butterflies utilised dark environments for thermoregulation and, because these conditions were widespread throughout the forest, the butterflies were able to move widely. The September–October generation, however, preferred intermediate light conditions, which tended to be restricted to the forest edge; as this was a relatively small area, butterfly movement was restricted.     

Population structure and sexual maturity of Aegla castro (Decapoda,Anomura), an endemic freshwater crab from Brazil

Specimens of Aegla castro Schmitt, 1942 were monthly sampled from June 2012 to May 2013 from Couro stream (23°57′15″S 51°06′00″W), located in the Upper Paraná river region, southern Brazil. Population structure, morphometric and functional maturity were analyzed. Allometric growth analysis on chela dimension versus carapace length (CL) was employed to recognize juveniles and adult individuals. Two sequential groups of adult males (morphotypes I and II) were recognized according to the state of development of the pair of claws. The CL where 50% of the population of individuals are adults (CL₅₀) was used to estimate the size at the onset of morphometric maturity. Males attain morphometric maturity at same size class of females (8.0–9.0 mm CL). Males and females are heterochelous and they often show the left chela more developed. The reproductive period was extended from June to September 2012 and April to May 2013 (six months) with record of 22 ovigerous females. The recruitment occurred in the months following the reproductive period, with higher records in October and December 2012. All the information gathered here should be useful to better understand the biology of the species studied.     

Reproduction of the introduced oyster Crassostrea gigas (Bivalvia: Ostreidae) cultured on rafts in Spain

The oyster Crassostrea gigas was introduced in Spain for aquaculture purposes; however, until now, it is not known whether populations are established in the wild, being necessary to define whether this species is spawning and which environmental variables trigger this process. The influence of environmental parameters on the reproduction of C. gigas was evaluated from January 2008 to October 2009 with oysters grown on a raft in the Ría de Arousa (Galicia, NW Spain). Temperature and chlorophyll a are directly correlated to sexual maturation. Oysters can mature at temperatures below 14°C. The temperature necessary for spawning differs between the sexes, requiring a temperature above 15°C for males and 18°C for females. Females had a single massive spawn between June and September, while males had partial spawning from May to December with two peaks, one in May–September and another in October–December, with the second peak more pronounced. The first spawning peak is related to high temperatures and concentrations of chlorophyll a, and the second spawning peak is mainly related to the food availability in the water. The spawning asynchrony may be impeding establishment of wild C. gigas populations in Spain.     

Life History of Ilybius fenestratus (Fabricius) (Coleoptera,Dytiscidae) in a Central Norwegian Lake

The life history of Ilybius fenestratus was studied in Målsj?en, a lake in S?r-Tr?ndelag, Central Norway (63°14'N, 10°26'E), during 1971–1972. Adults and larvae were sampled in activity traps every week during March–October and every 2–3 weeks during November–February. Newly-emerged adults were generally found from mid-July to September, and after overwintering in torpidity, probably in the water, they again appeared in the second half of June to August/September. Laying of eggs took place from early/mid July to early August. Larvae occurred in the traps from late July to early May. I. fenestratus was thus found to be a semivoltine summer breeder, with overwintering larvae the first winter and overwintering adults the next. Both adults and larvae lived in large areas of the lake's littoral zone.     

Atlantic sturgeon Acipenser oxyrinchus Mitchill, 1815 seasonal marine depth and temperature occupancy and movement in the Bay of Fundy

Pop‐up satellite archival tags were used to collect fisheries‐independent data that characterized the seasonal habitat occupancy and movement of Atlantic sturgeon Acipenser oxyrinchus Mitchill, 1815 in the Bay of Fundy (BoF). Atlantic sturgeon from Canadian and United States stocks aggregate annually for feeding in Minas Basin, inner BoF (45.28N, 64.18W), during May to September but depart to other locations from October to April. Sixteen PSAT tags were applied to sturgeon ranging from 152 to 203 cm total length captured and released in Minas Basin during May to August. Ten of the tags were reported after 1 year at large and provided pop‐off locations. Seven were recovered with archived data, or provided transmitted data sets, which were analyzed for depth and temperature occupancy from June 2011 to August 2013. During June to August while in the Minas Basin the sturgeon spent >90% of time at depths <10 m and temperatures of 16–22°C. Departure from Minas Basin through the Minas Passage was in September and October, when depth occupancy varied from <10 to 120 m. From November to April sturgeon were in the outer BoF, where mean depth occupancies ranged from 40 to 100 m at mean temperatures of 3–14°C. Deepest mean depth occupancy of 60 to 90 m was recorded during December 2011 and 2012, and coldest mean temperature occupancy of 0–4°C in March 2011 and 2012. During April and May mean depth and temperature occupancy ranges shallowed from 40 to <10 m and increased from 4 to 15°C, respectively. Tag pop‐off locations indicated that sturgeon spent the winter season in the outer BoF but by June had either migrated back to the Minas Basin or off the mouth of the Saint John River, a known spawning location.     

An atypical reproductive cycle in a common viviparous Asia Agamid Phrynocephalus vlangalii

Viviparous lizards living in cold climate of high altitude often exhibit atypical reproductive cycles, in which mating and fertilization occur synchronously and annually with parturition occurring at the end of the year. Nevertheless, detailed case studies on atypical reproductive cycles are few. Using anatomical data combined with behavioral observations, we examined the reproductive cycle of a common Asian agamid, Phrynocephalus vlangalii, from a high‐elevation area in Sichuan, China. Male spermiation of P. vlangalii occurred in May, and spermatogenesis began in June and reached a maximum in October. For females, ovulation and fertilization occurred in May, and females developed gestation and pregnancy in 3 months from June to August, without vitellogenesis during this period. Females gave birth synchronously in late August, then vitellogenesis began and lasted until May of the next year. All adult males and females were synchronized in the same reproductive condition each month. The synchronous and annual reproductive cycle of P. vlangalii clearly represents an atypical cycle. The male courtship and mating behaviors were concordant with gonadal cycle and mainly happened in May and June. Despite the short growth period for neonates, they had a high over‐winter survival rate of 84.4%, suggesting that autumn parturition did not generate high costs to this reproductive cycle. We propose that the high over‐winter survival rate of neonates is likely linked with female delayed sexual maturity, female asynchronous vitellogenesis and gestation, large relative clutch mass (RCM), and adult‐offspring burrow sharing behavior during hibernation.