Reproductive Strategies of <Emphasis Type="Italic">Trachypithecus pileatus</Emphasis> in Arunachal Pradesh,India

We studied reproductive behavior of free-ranging capped langurs (Trachypithecus pileatus) in the Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. Four species of primates —Trachypithecus pileatus, Macaca mulatta, M. assamensis, and Nycticebus bengalensis— live there. We studied the mating seasons, mating frequency, copulatory attempts, time spent in copulation, and interval between 2 successive copulations, gestation length, and interbirth interval of 4 groups of capped langurs during 2001–2003. We observed 2 mating seasons in a year. The first was larger, comprising 5 months (September–January), and the second was short, April and May. Mating was intensive in the morning session (0600–1000 h); 57% of total mating events occurred then. The average gestation period was 200 d. November was the most favorable month for breeding. In a year, 107 mating events occurred involving 5 adult females. Average time per mounting attempt is 12 s. Duration of mounting was the maximum in November. Interbirth interval was 23 months and 10 d. The birth season was 129 days, December–April; 53% of births occurred in February and March. Average birth rate is 0.386 birth/female/yr.     

Ontogenesis of the cricket Gryllus argentinus Sauss. (Orthoptera, Gryllidae)

The development of Gryllus argentinus Sauss. was studied under stable laboratory conditions: the temperature of 26°C, the air humidity of 60%, and the photoperiod of 12h light: 12 h dark. The life cycle of Gryllus argentinus includes four stages: egg, pronymph, nymph, and adult. The duration of embryonic development is 18 days. The depth of egg bedding in the peat is 9.63 ± 0.12 mm (n =145), the clutch containing 2–4 eggs. A female can lay over 1100 viable eggs during the entire oviposition period. Nymphal development includes 9 instars and lasts 97 days. The duration of nymphal instars (days) is: I—5; II—6; III—6; IV—6; V—8; VI—10; VII—13; VIII—14; IX—29. The duration of the adult life is 51 days in males and 69 days, in females. In the imaginal ontogenesis of males and females, three periods can be distinguished: pre-reproductive, reproductive, and postreproductive. Males start to emit the aggressive signal on the 6th (5–8th) day (the pre-reproductive period). They enter the reproductive period (start to emit the calling song) on the 9th (8–13th) day. Females enter the reproductive period (become capable of responding to the calling song and of copulation) on the 9th (8–10th) day. Oviposition starts on the day after the first copulation. The reproductive period lasts about 40 (15–59) days in males and 58 (21–70) days in females. The post-reproductive period starts in females at the moment of finishing the egg laying period and in males, with disappearance of reproductive behavior. The period ends in the animal’s death.     

Influence of diet and photoperiod on development and reproduction of European populations of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

The current study examines the effect of photoperiod (16:08 or 12:12 h L:D) and diet (eggs of Ephestia kuehniella Zeller (Lepidoptera: Phycitidae) or the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae)) on the development and reproduction of the multicoloured Asian lady beetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). A long-term laboratory population of H. axyridis (since 1998) and a melanic and non-melanic population originating from field collected individuals of H. axyridis in Belgium were used in this study. Long day conditions (16 h photoperiod) shortened development of the field populations with 2–3 days when compared with short day conditions (12 h photoperiod). Oviposition in the field populations was delayed by 1–3 months when reared at a 12 h photoperiod. Dissections indicated that the females were in reproductive diapause. As compared with live pea aphids, a diet consisting of E. kuehniella eggs yielded heavier adult body weights (up to 12%) and increased the number of egg laying days (by 45–169%) for both field populations at a 16 h photoperiod and lengthened adult life span (by 45–92%) under both light regimens. The morph types differed in their response to the foods offered in terms of developmental rate, pre-oviposition period and number of oviposition days. The laboratory and field strains responded differentially to regimens of food and photoperiod. The study indicated a greater nutritional plasticity of the non-melanic morphs which may offer them a competitive advantage that may in part explain the predominance of non-melanic morphs in newly colonized areas.     

Biology and population development ofAblattaria arenaria [Coleoptera: Silphidae], a snail predator

The biology ofAblattaria arenaria (Kraatz) was studied in the laboratory by using a helicid snail,Xeropicta derbentina (Kyrnicki) as prey. Population development ofA. arenaria in the field was studied in 1985 and 1986. The eggs ofA. arenaria were laid in the soil in lots of 5–45 at various intervals, and the total number of eggs per female varied from 144 to 193 during the oviposition period of 24–88 days.A. arenaria passed through the egg, 3 larval, prepupal, and pupal stages before reaching the adult stage. The mean duration of these stages was 9.8, 3.9, 2.5, 5.9, 3.8 and 5.7 days, respectively, with a total of 31.4 days. A. arenaria overwintered as an adult and became active and laid eggs during the spring. The start of spring activity seemed to be highly influenced by relative humidity. High humidity resulted in early emergence from overwintering sites. There was 1 generation in 1985, but 2 population peaks occurred in 1986. Immature stages of the 2nd generation became adult before the beginning of aestivation. Activity of the beetles was stopped by the beginning of hot weather in June, which synchronized well with the beginning of snail aestivation.      

Isolated, distal blade discs of the brown alga Laminaria digitata form sorus, but not discs, near to the meristematic transition zone

Blade discs of vegetative thalli of Laminaria digitata (Huds.) Lamour. from Helgoland (North Sea) cut at 5–15 cm distance from the blade/stipe transition, formed sorus in the laboratory after 7–12weeks, 5 months earlier than whole fronds in the field. Sorus formation occurred in a broad range of daylength regimes or temperatures, at 8–16 h light pe rday and 6–12 ^°C. No sorus was developed during three months by meristematic blade discs cut from the lowermost 3 cm portion of the blade, nor from whole thalli cultured in parallel to isolated blade discs. These findings point to the possible existence of sporulation inhibitors produced by the laminarian meristem. This revised version was published online in August 2006 with corrections to the Cover Date.     

The role of oxygen availability in the embryonation of Heterakis gallinarum eggs

The importance of oxygen availability in the embryonation of the infective egg stages of the gastrointestinal nematode parasite Heterakis gallinarum was studied in the laboratory. Unembryonated H. gallinarum eggs were kept under either aerobic conditions by gassing with oxygen, or anaerobic conditions by gassing with the inert gas nitrogen, under a range of constant temperatures. Oxygenated eggs embryonated at a rate influenced by temperature. Conversely, eggs treated with nitrogen showed no embryonation although when these eggs were transferred from nitrogen to oxygen gas after 60 days of treatment, embryonation occurred. This demonstrated that oxygen is an essential requirement for H. gallinarum egg development, although undeveloped eggs remain viable, even after 60 days in low oxygen conditions. The effects of climate on the biology of free-living stages studied under constant laboratory conditions cannot be applied directly to the field where climatic factors exhibit daily cycles. The effect of fluctuating temperature on development was investigated by including an additional temperature group in which H. gallinarum eggs were kept under daily temperature cycles between 12 and 22°C. Cycles caused eggs to develop significantly earlier than those in the constant mean cycle temperature, 17°C, but significantly slower than those in constant 22°C suggesting that daily temperature cycles had an accelerating effect on H. gallinarum egg embryonation but did not accelerate to the higher temperature. These results suggest that daily fluctuations in temperature influence development of the free-living stages and so development cannot be accurately predicted on the basis of constant temperature culture.     

A meat-based diet for rearing the predatory stinkbugsPodisus maculiventris andPodisus sagitta [Het.: Pentatomidae]

A diet based on bovine meat was evaluated as an alternative food source for rearing the predatory bugsPodisus maculiventris (Say) andPodisus sagitta (Fabricius). Thus far, 7 and 5 continuous generations of the respective species have been reared on this diet. In comparison to rearing on larvae of the greater wax moth,Galleria mellonella (L.), however, nymphal development was prolonged with 15–40% and adult weights were lower, reaching 72–82% of the control weights. Fecundity of females reared on the meat diet was reduced to about 1/3–1/2 of that of the control, but egg weight and egg fertility were comparable with those in cultures fed live prey. Results obtained for laboratory rearing on this medium were generally better forP. maculiventris than forP. sagitta.      

Recruitment of amphidromous sleepers Eleotris acanthopoma, Eleotris melanosoma, and Eleotris fusca into the Teima River, Okinawa Island

Recruitment courses of three amphidromous sleeper species, Eleotris acanthopoma, E. melanosoma, and E. fusca, were investigated at the surf zone adjacent to the river mouth and at five stations in the Teima River on Okinawa Island, Japan. All three species occurred at the surf zone as pelagic larvae with transparent and compressed body, a conspicuous air bladder, and an emarginated caudal fin. Eleotris fusca (16.0–19.6 mm in standard length: SL) sometimes possessed a vestige of the larval chin barbel and were larger than E. acanthopoma (9.7–13.2 mm SL) and E. melanosoma (11.2–12.8 mm SL). The pelagic larvae were also collected during full tide from the lower reaches of the tidally influenced area of the river. The pelagic larvae may be carried in and out of the estuary with some tidal fluxes, and they may settle when they reach the upper tidally influenced area where the salinity becomes extremely low. Body width and pigmentation of newly settled larvae increased. E. fusca was considered to migrate upstream to the freshwater area against the flow of the river just after reaching the settled stage. After settlement, all three species became completely pigmented, the caudal fin became round in shape, and the fin ray counts became complete with growth. Also, E. acanthopoma dispersed widely to the lower part of the tidally influenced area or to the lower reaches of the freshwater area, E. melanosoma dispersed to the lower part of the tidally influenced area, and E. fusca dispersed upstream.     

Effect of pH on survival,reproduction, egg viability and growth rate of five closely related rotifer species

In the laboratory we examined the effect of pH (5–10 with one interval) on survival, reproduction, egg viability and growth rate (intrinsic growth rate—r _m and population growth rate—r) of five Brachionus rotifer species (B. calyciflorus, B. quadridentatus, B. urceolaris, B. patulus and B. angularis). The pH was shown to exert a major influence on egg viability and growth rate (r _m and r) for each species. The age-specific survivorship curves within a species were not significantly different at pH 6–10. The optimal pH for each species is near-neutral pH (pH 6–8), and the fecundity decreased as the pH deviated from these values. For each Brachionus species, there was no significant difference between age-specific fecundity curves at pH 7 and 8. At acid pH (pH 5 or 6) higher egg mortality was observed for each species. The r _m and population r of the five Brachionus species incubated at different pHs were significantly influenced by pH. The pH supporting the highest r _m or r was obtained at pH 6–8, but varied due to species. In this study B. urceolaris and B. patulus could tolerate a broad range of pH, while the populations of B. calyciflorus, B. quadridentatus and B. angulari declined at acid conditions.     

Effects of daylength,irradiance and settlement density on the growth and reproduction of <Emphasis Type="Italic">Undaria pinnatifida</Emphasis> gametophytes

The effects of daylength, irradiance and spore settlement density on the growth, maturation and sporophyte production of Undaria pinnatifida (Harvey) Suringar gametophytes were examined using a factorial experimental design in culture. The growth of Undaria gametophytes increased with increasing daylength (8, 12 and 16 h), but the maximum fertility occurred at a daylength of 12 h followed by 8 and 16 h. Gametophytes grew better at the 16 h daylength under the same mean daily irradiance (MDI) of 20 μmol photons m⁻² s⁻¹. However, the fertility was higher at the short daylength (8 h), indicating that the maturation of U. pinnatifida gametophytes is influenced by daylength rather than by the MDI. Vegetative growth and sporophyte production of gametophytes were better at 60 μmol photons m⁻² s⁻¹ than at 30 μmol photons m⁻² s⁻¹ under a 8:16 h LD (Light: Dark) cycle, and their growth and maturation were density-dependant in 16 and 12 h daylength, respectively. These results suggest that the U. pinnatifida gametophytes require a certain amount of light for the growth and reproduction, and intraspecific competition occurred under the optimal growth and maturation conditions. However, the sporophyte recruits per unit has been enhanced with increasing spore settlement density at 8 and 12 h daylengths indicating that high settlement density gives a benefit for maintaining population, even though the sporophyte production of each female plant is inhibited. In conclusion, the vegetative growth, reproduction and sporophyte production of U. pinnatifida gametophytes are retarded at a low irradiance above growth saturation and a high settlement density, and are determined by daylength.     

Callus induction and thallus regeneration from callus of phycocolloid yielding seaweeds from the Indian coast

The tissue culture of phycocolloid yielding seaweeds included preparation of axenic explants, callus induction, subculture of excised callus and regeneration of plantlets from pigmented callus in the laboratory. Treatment of algal material with 0.1–0.5% detergent for 10 min and 1–2% betadine for 1–5 min and 3–5% antibiotic treatment for 48–72 h successively enabled viable axenic explants to be obtained as high as 60% for Gracilaria corticata, Sargassum tenerrimum and Turbinaria conoides and 10% for Hypnea musciformis. Callus induction was more conspicuous in T. conoides than in the other three species investigated. Of the irradiances investigated, 30 μmol photons m⁻² s⁻¹ produced calluses in as many as 40% explants in G. corticata and T. conoides and 10% in H. musciformis and S. tenerrimum. The explants cultured at 5 and 70 μmol photons m⁻² s⁻¹ did not produce any callus in all the species studied except for H. musciformis in which 10% explants developed callus at 5 μmol photons m⁻² s⁻¹. Most of the species investigated showed uniseriate filamentous Type of growths and buds from cut ends and from all over the surface of explants. Nevertheless, T. conoides had three Types of callus developments, namely (1) uniseriate filamentous Type of outgrowths from the centre of the cut end of explant, (2) bubbly Type of callus and (3) club-shaped callus clumps. The subculture of T. conoides callus embedded in 0.4% agar produced two Types of filamentous growth, namely filiform (with elongated cells) and moniliform filaments (with round cells) in the 2 months period after inoculation. Further, friable callus with loose cells was also found associated with excised callus. The moniliform filaments showed prolific growth of micro-colonies resembling to somatic embryo-like growth which, in liquid cultures, differentiated and developed into propagules with deformed shoots and distinct rhizoids. The shoots of these propagules remained stunted with abnormal leaf stalks without forming triangular shaped leaves as the parental plant and rhizoids had prolific growth in the laboratory cultures. The excised callus of G. corticata continued to grow when transferred to liquid cultures and showed differentiation of new shoots within 10 days. The shoots grew to a maximum length of 5–6 cm in the 2 months period in aerated cultures in the laboratory. Dedicated to the memory of Late Dr. Rangarajan.     

Sexual initiation in wild mountain gorillas

A field study of wild mountain gorillas was conducted to elucidate details of sexual initiation required for an interpretation of the increased frequency of copulation during the menstrual cycle, in comparison to the wild, that occurs when this species is tested in traditional laboratory pair tests. Although females in the wild played a clear role in establishing and maintaining proximity to the male and assertively presenting for copulation, all female presenting was preceded by some form of behavior by the male. Of particular relevance were several components of the male’s chest-beat display that had been observed at much higher frequencies in the laboratory tests. Although originally described as male aggression in the laboratory tests, such behavior now appears to be male sexual initiative, elicited by female proximity. The exaggerated form and frequency of the display in the laboratory, and the increased copulation during the cycle that ensued, are likely due to (1) placing females in proximity to a male daily, rather than on 2–3 days of estrus as occurs in the wild, and (2) the inability of the female in the laboratory to withdraw from male proximity during pair tests in a single cage. In addition to clarifying the data on laboratory pair tests, the data on wild gorillas have relevance to the captive breeding of gorillas.     

The Life Cycle of Lestes viridis (Odonata: Lestidae) in Two Seasonal Streams of the Sierra Morena Mountains (Southern Spain)

The life cycle of the zygopteran odonate Lestes viridis in two seasonal streams in the Sierra Morena Mountains is inferred from size-frequency analyses of handnet samples of larvae and records of presence and reproductive activity of adults during three consecutive years. The egg stage (duration 5–6 months) overwinters, larval development is brief (6–8 weeks) and adults undergo a protracted, prereproductive, summer diapause (up to 3 months) before mating and ovipositing in late September, about one week after the first appreciable fall of rain, but before surface water reappears in the streams after having been absent for about four months during the hot, dry summer. Comparison between this life cycle and those of more northerly populations reveals a latitude-correlated cline in phenology resembling that found in some other northern hemisphere odonates that, like L. viridis, maintain an obligatorily univoltine life cycle at different latitudes.     

Responses of Hedysarum Laeve , a guerrilla clonal semi-shrub in the Mu Us sandland, to local sand burial

In arid and semi-arid inland deserts, one of the environmental stresses for plants is recurrent sand burial, which can influence the physical and biotic microenvironments of the plants and soil. Previous studies have shown that different levels of sand burial have different effects on plants. Slight sand burial could increase the height increment, leaf biomass and the number of new ramets of the plants while heavy sand burial could impair the growth of the plants and even decrease their chances of survival. In other words, below a certain threshold level of burial, the growth of plants is stimulated probably because of multiple factors. However, as the level of burial increases, the positive response starts to decline until it becomes a negative value. Arid and semi-arid inland deserts are frequently colonized and stabilized by many rhizomatous clonal plants. Clonal physiological integration often helps clonal plants buffer local environmental stress encountered by ramets. A rhizomatous clonal semishrub, Hedysarum laeve (H. laeve), is the dominant plant species and important for vegetation restoration in the Mu Us sandland. To investigate whether clonal integration can increase the threshold of sand burial and help rhizomatous H. laeve tolerate heavy sand burial, we conducted a field experiment. The results showed that slight sand burial could accelerate ramet growth and enhance leaf biomass, stem biomass and shoot biomass, while heavy sand burial reducesed the biomass of the plant and impairs survival and growth of the ramets. Clonal integration increased the threshold of sand burial. Under heavy sand burial, ramets connected to other ramets not buried in sand were more in terms of height increment, stem biomass, leaf biomass and shoot biomass compared to the ramets encountering sand burial but disconnected from other ramets. It suggested that clonal physiological integration could help H. laeve ramets tolerate relatively heavy sand burial. We also discussed that clonal integration plays a role in H. laeve presence in the Mu Us sandland. __________ Translated from Journal of Plant Ecology (formerly Acta Phytoecologica Sinica), 2006, 30(2): 278–285 [译自: 植物生态学报]     

Effects of copulation temperature on female reproductive output and longevity in the wolf spider Pardosa astrigera (Araneae: Lycosidae)

The copulation duration of male wolf spider Pardosa astrigera, was significantly influenced by environmental temperature, as had been found in some insect species. Therefore, temperature during male courtship and copulation may influence the amount of sperm and seminal fluids transferred during copulation, which in turn could influence female fitness. In order to test this hypothesis, we subjected pairs of male and female P. astrigera to five temperature groups from 16 to 32 °C at an interval of 4 °C, and investigated whether and to what extent the various temperatures during male courtship and copulation influenced female reproductive output and female adult longevity under controlled laboratory conditions. With the increase of copulation temperature, females were more likely to lay egg sacs. The total egg sacs and lifetime fecundity of female were positively influenced by copulation temperature, whereas female lifetime spiderlings and adult longevity were independent of copulation temperature.     

The spectral responses of a submerged plant <Emphasis Type="Italic">Vallisneria spiralis</Emphasis> with varying biomass using spectroradiometer

The relationship between land features and their spectral characteristics is a key for the interpretation of remote sensing images. This study was designed to investigate the spectral responses of Vallisneria spiralis, a common submerged aquatic plant in Shanghai, with varying biomass both in the laboratory and in the Middle Lake section of a field-scale constructed wetland, using a FieldSpec™ Pro JR Field Portable Spectroradiometer. The results showed that the reflectance rate of V. spiralis increased with its increasing biomass, and this was exhibited both at the visible band (500–650 nm) and the near infrared band (700–900 nm). The water environment influenced the reflectance rate and the primary differences between the laboratory and field results mainly occurred at the near-infrared band (700–900 nm). A regression analysis was carried out between the biomass of V. spiralis and the reflectance rate at the wavelengths of QuickBird™ bands where the biomass responded most strongly. The results of this analysis showed a clear linear relationship by which the biomass of V. spiralis could be quantitatively deduced from the reflectance rate measured in situ. The implications of this observation, in terms of the ability of hyperspectral remote sensing to estimate and monitor the distribution and dynamics of submerged aquatic vegetation on a large scale, are discussed. Handling editor: S. M. Thomaz     

Larval behaviour and choice of settlement site: Correlation with environmental distribution pattern in an erect bryozoan

Summary This paper concerns the preferred environmental conditions for settlement and metamorphosis of larvae of the erect, rigidly calcified cheilostome bryozoanSchizotheca serratimargo and compares the settlement preferences with in situ distribution of adult colonies. A review of bryozoan larval behaviour and responses to environmental parameters is given in order better to understand larval settlement and metamorphosis in this species. Release of larvae ofS. serratimargo (Hincks) was induced so that each travelled down a path with a limited set of microenvironments in which it could choose to settle. Four different flow velocities, three different depths below the water surface, two different light intensities, three different orientations of plexiglas surfaces, and subdivision of distance of travel into three segments, yielded 216 microenvironments. 466 larvae successfully settled and metamorphosed within the experimental chamber. They metamorphosed in significantly higher numbers in microenvironments with low flow velocity, in the shallowest of the three possible depths, in darker areas, and on nonoverhanging surfaces with little or no sediment. The most important stimulus for settlement was darkness, especially where there was a strong gradient in light intensity.S. serratimargo grows as erect bilaminate bushes on protected flanks of boulders, in small caves, and just within the entrances of larger caves at depths of 5–30 m, as well as on hard debris on open muddy sand floors at 30–35 m depth in the Adriatic and Mediterranean Seas. The experimentally-determined settlement patterns suggest that recruitment is more important than post-settlement interactions or exposure to physical damage in determining local distribution of the species.     

Effect of interannual variations in sea-surface temperature on egg-laying parameters of black-tailed gulls (Larus crassirostris) at Teuri Island, Japan

Sea-surface temperature (SST) directly and indirectly affects the distribution and abundance of prey species for seabirds, so we expect variation in SST to be associated with variation in seabird life history traits. In black-tailed gulls (Larus crassirostris) at Teuri Island in northern Hokkaido, Japan, we investigated the diet of the gulls prior to egg laying in 2004 and 2005, and examined the influences of SST in March or April, when the gulls congregate in the colony, on egg-laying parameters using 13 years of data (1992–2004). The gulls fed on krill (Thysanoessa inermis) and fish prior to the egg laying. Mean first egg dates and clutch sizes were significantly and quadratically related to SST anomalies in March, but were not influenced by SST anomalies in April. There was no significant effect of SSTs in either March or April on egg volume. Sea-surface temperature anomalies in March of the years of early laying (−1 to 1°C) were higher than those in 2001 (−2.2°C), but lower than those in 1992 (+1.2°C) and 2004 (+1.1°C). Thysanoessa inermis congregates to spawn at the sea surface, when SSTs rise 3−4°C. Thus, a mismatch between food availability and the timing of egg production in the gulls could have occurred in these 3 years. This study suggests that SST fluctuations prior to laying are important in breeding success of black-tailed gulls.     

Studies ontrichogramma buesi as a biocontrol agent againstPieris rapae in Egypt

Trichogramma buesi was reared in the laboratory on eggs of the Mediterranean flour moth,Anagasta kuehniella. The incubation period of the parasite's egg was 27 h at 23 °C and 22 h at 27 °C. The larval stage lasted 3.6 and 3.2 days, the pre-pupa lasted 16 and 23 h, and the pupa lasted 5.4 and 4.6 days at 23° and 27°C, respectively. The total developmental time (from egg to adult) averaged 9.2, 9.4, and 9.1 days when the parasite was reared on eggs ofPieris rapae, Spodoptera littoralis, andA. kuehniella, respectively, at 27 °C. Sex ratio inT. buesi was 1 ♂: 1 ♀ in nature and 1 ♂: 1.3 ♀ in the laboratory. The daily and total numbers or progeny produced/female were 5.1 and 98.2 adults, respectively. The parasite female, fed on honey, lived 10.7 days at 27 °C and 12.1 days at 23 °C. Percentages of parasitism byT. buesi on eggs ofP. rapae collected from cabbage fields ranged between 0 and 31.5 % in 1985 and betwcen 0 and 36.4% in 1986 during July through December. The respective figures on eggs collected from turnip fields were 16–42.2% and 12.5–32.1% during November and December.