On the reproductive biology of the herbivorous spiny-tailed agamid Uromastyx philbyi in western Saudi Arabia

Abstract

The reproductive biology of the Spiny-tailed Agamid Uromastyx philbyi, a herbivorous desert lizard, was studied in western Saudi Arabia. Reproduction is seasonal, with mating in early spring (March), oviposition in late spring (May–June), and hatching in summer (July). The mean clutch size was 6.67 eggs. Eggs are large (mean mass = 7.48 g) and relative clutch mass (RCM) averaged 0.49. Clutch mass and RCM increased with increasing egg mass. Clutch size, egg size, clutch mass, and RCM were significantly correlated with maternal body size.     

Mating and reproduction of predaceous diving beetles,Dytiscus sharpi,observed under artificial breeding conditions

Mating season and embryonic development of the predaceous diving beetles, Dytiscus sharpi, (Coleoptera; Dytiscidae) were observed under artificial breeding conditions. Female and male adult insects started mating from November to March and gave first instar larvae mainly in April. When the mating was artificially delayed until February, first instar larvae appeared from the end of March to the middle of May. I also investigated the effects of temperature on larval development. Apparent hatchability of eggs was not affected by high temperature, however, their normal development after hatching was significantly interfered. Most of the first instar larvae kept at 20-25 degrees C from before hatching died within one day after hatching. By contrast, juveniles kept outdoors (7.0-20.9 degrees C) could develop at least until second instar larvae. Temperature >23 degrees C after hatching had no effects on larval development. From these observations, it was concluded that the reproduction strategy of Dytiscus sharpi, i.e. mating in late autumn and hatching in early spring would be the reasonable results of adaptation to the warm habitats where they are collected.     

Hochstetter's frog (Leiopelma hochstetteri) egg,mobile larvae and froglet development

Egg strings and larvae of Hochstetter's frog (Leiopelma hochstetteri) were located at three widely separated North Island sites: in seeps at Brynderwyns in December 2004, in an open pool at Wharerino in March 2009, and in an underground pool near the Kaipawa Track, Coromandel, in late May 2009. Ten egg strings were also laid by captive frogs in water courses at Hamilton Zoo in April 2009. All egg strings held from 11 to 13 eggs. The egg strings laid in the Brynderwyns were regularly observed until metamorphosis was completed in March 2005. Twenty-four swimming larvae emerged from 25 capsules at c. 40 days after discovery, and at least 14 froglets were produced at c. 90 days. All of them developed in darkness, in a 120 ml pool <30 mm deep. The emerged froglets ranged from 9.8 to 10.8 mm snout-vent length. The detection of eggs, larvae and <11 mm froglets indicates that the egg laying period is at least from late September to May.     

Seasonal reproductive cycle in relation to tolerance to high temperatures in the terrestrial slug Lehmannia valentiana

Abstract. Seasonal maturation of the gonad (hermaphrodic gland) was examined in the terrestrial slug Lehmannia valentiana in Osaka, Japan. The ratio of the gonad weight to body weight was low in June–September, rapidly increased in October, and gradually decreased thereafter. In May–September, most slugs had only spermatogonia and spermatocytes, and all slugs had mature sperms in October–April. The oocyte size increased in September and large oocytes were observed in late October–April. Under natural temperature and photoperiodic conditions in Osaka, slugs laid eggs in early November–May. Therefore, this species reproduces from late autumn to spring, in contrast to many terrestrial slugs. In January–early February, however, the number of laid eggs was small and oviposition activity showed a bimodal seasonal pattern. In contrast, the hatching pattern was unimodal and most hatching was observed in spring. After a 1-h exposure to 33°C, the survival rate was 100% in juvenile slugs but 0% in eggs. Although hatching success was >85% at 15°–20°C, no eggs hatched when they were maintained at 25°C. The heat susceptibility of eggs in this species may be one of the key factors restricting oviposition from late autumn to spring.     

西藏飞蝗的生物学特性

西藏飞蝗Locusta.migratoria tibetensis Chen在四川甘孜州1年发生1代,某些地方(乡城县)1年发生不完整的2代,即以卵越冬,翌年3月下旬开始孵化出土,4月中、下旬为孵化盛期,1~3龄始盛期为4月中旬~5月中旬,高峰期为5月下旬,7月上旬初始羽化,7月下旬~8月上旬为羽化盛期,8月上旬始见产卵,8月下旬~9月上旬为产卵盛期,第1代成虫较早产下的卵块在条件适宜的情况下可于当年9月上旬孵化出土,但孵化出的蝗蝻不能越冬。该虫卵、全蝻期及全世代的发育起点温度分别为14.2,16.1,14.6℃,有效积温为179.1日.度、360.0日.度、787.8日.度。在18,21,24,27和30℃等5种恒温条件下其平均世代历期214.4,133.3,79.2,66.3和50.7d。     

Plasticity of Lythrum salicaria and Phragmites australis growth characteristics across a European geographical gradient

Plants of Lythrum salicaria and Phragmites australis originating from localities across the European north–south geographical gradient were cultivated in parallel in an outdoor tub experiment. A strong correlation was found between growth and morphometric characteristics related to plant size (plant height, basal diameter, aboveground- and belowground plant biomass, etc.) and the position of the respective populations along the north–south gradient. Plants of both L. salicaria and P. australis from the southern localities grew taller and more vigorously and flowered later than plants from relatively more northern localities. From this point of view, the plants originating from south European populations were comparable to invasive North American plants. Our study indicates that explanation of the competitive success of populations invading new geographical areas may involve the role of geographic gradients within the species native range.     

Factors affecting nesting success in the Great-crested Grebe Podiceps cristatus at Lake Tonga,north-east Algeria

The breeding ecology of the Great-crested Grebe Podiceps cristatus was investigated over four consecutive years (2009-2012) at Lake Tonga, north-east Algeria. In all four years, the egg-laying period was relatively short, spanning two months (end of March to end of May), and bimodal. Nests were mainly located in Phragmites australis, over water of substantial depth (178 ± 43?cm, N=209), far from the shore and in habitat with low vegetation cover (12.37 ± 7.67%, N=209). The overall clutch size was 3.73 ± 0.92 eggs (N=127) and it decreased marginally over time. The overall nesting success was 70.4% (N=209), with nest failure caused mainly by predation (65%) and flooding (23%). Breeding outcome was significantly and positively related to nest size, with bigger nests conferring better survival to eggs and young probably through affording better protection during spells of adverse weather. However, the benefits of bigger nests may be confounded by the age or intrinsic quality of birds. The location of nests in P. australis, rather than other vegetation types, increased nesting success marginally but significantly. Two cases of interspecific mixed clutches involving the Great-crested Grebe were recorded.     

Reedbed selection and colony size of breeding Purple Herons Ardea purpurea in southern France

Reedbeds of Phragmites australis have declined in Europe in recent decades. Moreover, in some European countries the remaining reedbeds are intensively managed for industrial reed cutting, hunting or grazing. Several species of conservation concern, such as herons and pelicans, use reedbeds as their principal breeding habitat. At the same time, data on habitat use and colony size of these species in relation to reedbed management practices are scarce. We investigated habitat characteristics of 71 reedbeds occupied or unoccupied by breeding Purple Herons Ardea purpurea in the Rhône delta (Camargue) and in other Mediterranean coastal marshes in southern France. In addition, data on colony size in occupied reedbeds were collected from aerial surveys. Reedbeds occupied by breeding Purple Herons were unharvested, or only partially harvested, in winter and had higher water levels in spring compared with unoccupied reedbeds. A logistic regression model with reed harvesting intensity and water levels in mid‐April as independent variables correctly classified reedbed use for 94.7% of the reedbeds in the study. A model with water levels in mid‐April alone was only 90.9% accurate, suggesting that low water level in spring is the most important factor limiting reedbed occupation by breeding Purple Herons. A general linear model indicated significant effects of harvesting intensity and reedbed surface area on colony size. Within occupied reedbeds there was a strong tendency for colony size to increase with increasing reedbed surface area. Given the recent developments in reed harvesting and wetland management in southern France and elsewhere in Europe, these results provide the first information on potential effects of these practices on reed nesting herons, and suggest that Purple Heron conservation is likely to be favoured by maintaining large uncut reedbeds with relatively high water levels in spring. The possible effect of changes in habitat on the Purple Heron population in southern France is discussed.     

Life-cycle variation inPanonychus akitanus Ehara (Acarina:Tetranychidae)

The life history ofPanonychus akitanus Ehara was studied in two Hokkaido populations on dwarf bamboos. The Sapporo population overwintered both as egg and female adult onSasa senanensis, and the Tomakomai population overwintered as egg onSasa apoiensis. Mites of the Sapporo population produced four or five generations from late April to late November or early December. The eggs that had overwintered began to hatch in mid-May, and this hatching period overlapped with that of eggs laid in late April by females that had overwintered. Therefore, mites with different overwintering stages would interbreed. Most eggs that had overwintered in the Tomakomai population hatched in mid-May, and about four generations were produced before early December, when only eggs were found. The density of mites per leaf of the Sapporo population reached a maximum in early May on old leaves and in late June on new leaves, and thereafter gradually decreased. The Tomakomai population initially decreased in density after hatching in the spring, but rapidly dispersed to new leaves, reached a peak in early September, and then gradually decreased. The maximal density was about 10 times higher and the distribution was less clumped (lower values of the aggregation index,m/m) than that of the Sapporo population. This was probably because the Sapporo mites could utilize only the underside of sporadically distributed leaves which were curled by spiders, whereas the Tomakomai mites inhabited any part of the leaf undersurface of the hairy host plant. Predators observed were phytoseiid mites and larvae of gall midges. The predatory effect on the Sapporo population was not clear. In the Tomakomai population, the number of gall midges correlated with the number of spider mites better than that of phytoseiid mites.     

Post‐hibernation ovary development in queens of the Japanese giant hornet Vespa mandarinia (Hymenoptera: Vespidae)

Ovary contents and insemination status were examined in overwintered queens of Vespa mandarinia that were collected using bait traps in Ibaraki Prefecture, eastern Japan. Catches in the traps occurred from late April to early July in 1999, though they were few or rather sporadic in and after June. Fertilization rates were 100% in 1999, and 93% in 1998 when a preliminary sampling was made. While the ovary index (number of eggs with size equal to or larger than adjacent nurse cells) of queens caught on the first few collection dates was small, it rapidly increased up to late May. Generalized linear model analyses showed that the ovary index depended both on collection date and the size (head width) of the queens. Mature eggs were almost absent in their ovaries before early May, whereas more than 70% of the queens had one or more mature eggs on and after May 10, suggesting the onset of nesting in early May.     

Reproduction characteristics of a stunted population of rudd, <Emphasis Type="Italic">Scardinius erythrophthalmus</Emphasis> (Linnaeus, 1758) living in the Anzali Lagoon (the southwest Caspian Sea,Iran)

A total of 486 specimens of Scardinius erythrophthalmus caught in the Anzali lagoon, a large lagoon located in the southwest Caspian Sea (Iran), between March and June 2007 were examined. Age determination showed that the maximum ages observed were 4+ in males and 5+ in females. Isometric growth was identified from length-weight relationship in males, females and pooled data. There was no significant difference from parity in the overall sex ratio of 252 males to 234 females. The fish spawn from mid April to late May, with peak spawning in mid May with the highest average GSI value of 7.12 and 13.52 for males and females respectively. The absolute fecundity ranged between 1482–59620 eggs with the mean of 9287.87 eggs while relative fecundity ranged from 127.8 to 1737.6 eggs/g with the average of 709 eggs/g of body weight. Egg diameter ranged from 0.43 to 1.23 mm with a mean of 0.73 mm. The characteristics of rudd in the stunted population from the Anzali lagoon differ markedly from those of other localities of its range.     

Some notes on the ecology of aquatic plants in the Al-Hammar marsh,Iraq

Aquatic plants were collected from different localities in the Al-Hammar marsh, southern Iraq, during late spring 1985. The marsh water is oligohaline. Typha angustata, Potamogeton pectinatus and Phragmites australis were the most abundant species in the study sites. The chemical composition of 15 aquatic plants in the study sites are given and compared with soil and water characters. These plants indicate variations among the species. All plants contain higher amounts of K than Na, while the opposite is found in the water. The Ca contents of plants and soil are higher than Mg.     

Inhibition of <Emphasis Type="Italic">Zizania latifolia</Emphasis> growth by <Emphasis Type="Italic">Phragmites australis</Emphasis>: an experimental study

The influence of Phragmites australis on the growth of Zizania latifolia, and the morphological characteristics of both species, were investigated at two nutrient levels. The experiment was carried out over three growing seasons between May 2003 and December 2005. The experimental plot was longitudinally divided into two equal halves, one of which was planted with Zizania latifolia (Zizania zone) and the other one with Phragmites australis (Phragmites zone). Four weeks after transplantation, the plot was again divided horizontally, perpendicular to the previous division, and subject to low (LN) and high nutrient (HN) treatments. Measured growth indices of the two species were more developed in the HN than in the LN treatments. Both species were observed to invade each other’s zone, but Phragmites latifolia seemed to out-compete Zizania latifolia individuals. This was evident from the decrease in below ground biomass of Zizania latifolia in the third growing season and deterioration in above ground organs with time. It was concluded that Phragmites australis out-competes Zizania latifolia due to better developed root and rhizome system.     

Seasonal changes in the reproductive and life-history traits of Chrysomela populi L. (Coleoptera: Chrysomelidae)

Seasonal changes in the reproductive and life‐history traits of Chrysomela populi L. were investigated in Shobara (34°52′N, 133°01′E), Japan, in 2004 and 2005. Larvae were hatched and reared under natural photoperiod and temperature in 8 different periods between late April and early September in 2004. The incidence of adult diapause increased with progression of the season in 2004. The critical timing of diapause induction, as defined by 50% of females entering diapause, was estimated to occur between late July and early August. No effects of season on the survival rate from hatching to adult emergence, percentage ovipositing females and percentage females that deposited viable eggs were clearly detected. Adult weight at emergence fluctuated seasonally, which was probably caused by air temperature. No effect of season on the oviposition period was observed among females that averted diapause. Females that entered diapause in 2004 started oviposition from the first day of May in 2005. Reproductive output was significantly greater in diapause females than in non‐diapause females. This increase in the reproductive output of diapause females was caused by elongation of the oviposition period and consequently by enlargement of the number of egg clutches deposited. These results suggest that the seasonal timing of diapause induction in females of C. populi would be affected by various risks and benefits to reproduction and survival.     

Relationship between arrival date, hatching date and breeding success of the white stork (Ciconia ciconia) in Slovakia

Changes in the spring arrival dates of migrant birds have been reported from a range of locations and many authors have focused on long-term trends and their relationship to temperature and other climatic events. Perhaps more importantly, changed arrival dates may have consequences for the breeding dates of birds which strongly influence breeding success. In this paper we take the opportunity provided by a monitoring scheme of the white stork (Ciconia ciconia) to examine several features of the timing of arrival and breeding in relation to chick production in Slovakia during the period 1978–2002. First arrival dates ranged from 5^th March to 30^th April, and hatching dates varied between 26^th April and 8^th July. Generally, early arriving pairs started breeding earlier and a shorter interval between the arrival of the first partner and breeding, expressed here as hatching date, resulted in higher breeding success.     

Seasonal prevalence of the Culex pipiens group (Diptera: Culicidae) larvae occurring in a puddle in the basement of an apartment building

The seasonal prevalence of the Culex pipiens group larvae occurring in a puddle in the basement of an apartment building was investigated from June 1993 to May 1994 (Period I), and from June 1994 to May 1995 (Period II). Totals of 25 237 individuals in Period I and 4989 individuals in Period II were collected: they were all C. pipiens group larvae, most of which were C. pipiens molestus. In Period I, the larvae occurred at a relatively low density in the hot months July and August; density began to increase from the cooler late September, peaked in late November, and was maintained at a high level until the third week of December. In Period II, in which mean air temperature was 5°C higher as of July and August than in Period I, larvae sharply decreased in number by one‐fifth of the total volume in Period I, and showed a peak density in the third week of July, and the peak continued until mid‐December. In Period I, the low temperature was favorable for oviposition activity of C. pipiens molestus, and accounts for the higher density of larvae in Period I than in Period II. C. pipiens molestus mostly stopped laying eggs between early December and late January. Larvae were not collected in March and April 1994 and in April 1995. However, considering that adult mosquitoes had been collected throughout the two periods except in March 1994, adults of C. pipiens molestus are thought to appear throughout the year.     

Field and laboratory studies on the timing of oviposition and hatching of the western black-legged tick, Ixodes pacificus (Acari: Ixodidae)

The timing of oviposition and hatching of Ixodes pacificus was investigated in the field and at constant temperatures in the laboratory. Replete females held at temperatures between 9 and 29°C began depositing eggs a mean of 9–70 days after drop off. Egg masses held between 12 and 25°C commenced hatching 25–178 days after the onset of oviposition. Eggs held at 9 or 29°C did not hatch. The lower temperature thresholds for development (LTD) for oviposition and hatching were 6.5 and 9°C, respectively. The number of degree days required for oviposition and hatching was 173 and 588, respectively. Replete females placed in the field on 2 December through to 8 March deposited eggs from 2 February through to 24 April; the eggs commenced hatching between 2 July and 21 August. Unfed larvae from two of 20 egg masses survived through the winter and fed readily when exposed to deer mice (Peromyscus maniculatus) on 22 April. Replete larvae were returned to the field and moulted between 9 and 21 August. Larvae exposed to deer mice in August, 4 weeks after hatching, also fed readily. Although further studies are needed to clarify the timing of nymphal development, the present study suggests that I. pacificus requires more than 1 year to complete its life cycle.     

Observations on the female reproductive cycles of captive Asian yellow pond turtles (Mauremys mutica) with radiography and ultrasonography

The annual reproductive cycle of 27 female Mauremys mutica was observed by radiography and ultrasonography from April 2006 to August 2007. Radiography was used to monitor clutch size and ultrasonography was used to monitor changes in the ovarian follicles. The follicles started to enlarge in September and became preovulatory in January. The mean maximum follicle diameter of ovulation was 18.30±1.44 mm, and ovulation occurred from March through August. Eggs were laid between April and August. Turtles entered latent period in early August and the maximum follicular size was at a low of 13.22±2.36 mm in late September. The vitellogenesis of the next reproductive cycle began in October. The 24 adult females laid 56 clutches containing a total of 227 eggs. Average clutch size was 4.05 eggs (range 1–8) and there were 2.33 clutches (range 1–4) per female. Egg shell images were first observed on the sixth or seventh day after ovulation. The oviductal period averaged 6.9 weeks (range 2–16 weeks) on the first clutch, 3.4 weeks (range 2–8 weeks) on the second, and 2.75 weeks (range 2–6 weeks) for the third. Radiography and ultrasonography are non‐invasive and convenient methods to evaluate the reproductive cycle of female M. mutica. They should be applicable to other turtles and should greatly enhance knowledge of reproductive physiology. Zoo Biol 29:50–58, 2010. © 2009 Wiley‐Liss, Inc.     

Seasonal Variation in Diel Production Pattern of Centropages tenuiremis in Xiamen Waters, China

The seasonal variations in diel production pattern, and egg hatching time of the copepod Centropages tenuiremis in Xiamen waters, China, were investigated between January and June of 2003. The results show that in the winter–spring (January to early May) the adult females tended to lay subitaneous eggs at night, while in the beginning of summer (late May–June) they tended to lay diapause eggs as well as subitaneous eggs during the daytime. The egg hatching time negatively correlated with water temperature. These results, combined with the fact that C. tenuiremis migrates vertically in Xiamen waters, may explain the reproductive strategy of this dominant species in winter–spring.     

Reproduction and growth of the black shore skink,Leiolopisma suteri (Lacertilia: Scincidae), in north‐eastern New Zealand

Reproduction and growth of a boulder beach population of the nocturnal skink Leiolopisma suteri on Motutapu Island were studied for 19 months. Epididymes contain sperm from April to November, and copulation probably occurs in October or November (spring). Ovulation occurs in late October or early November, and three or four (mean, 3.7) eggs are laid in late December. Incubation takes 3 months. Total development time from ovulation to hatching is 5 months, one of the longest development periods recorded for Scincidae. Growth to sexual maturity is slow, most females depositing their first clutch 33 months after hatching; males mature at 29 months.