Ultrastructure of the egg of Sanguinicola inermis Plehn, 1905 (Digenea: Sanguinicolidae)

Eggs of Sanguinicola inermis are the main cause of pathology in the definitive fish host. Eggs were collected from the common carp, Cyprinus carpio, and examined with transmission electron microscopy and optical histochemistry. Eggs, which lack microspines and pores, possess a thin shell with an outer surface of shallow reticulations and inner spherical projections. Internally the egg comprises a homogeneous acellular layer adjacent to a thicker syncytial, metabolically active layer. The latter layer is filled with glycogen and contains many excretory concretions, which are also present within the egg lumen. Portions of the syncytial layer extend towards the egg lumen and are in close proximity to the enclosed miracidium. Histochemical tests on the shell were negative for elastin.     

Pre-ovipositional and ovipositional behaviour of Lasioseius ometes (Oudemans) and Hypoaspis kargi Costa (Acari: Dermanyssiae: Ascidae,Laelapidae) with notes on egg protection strategies in Mesostigmata

Egg deposition by the soil mites Lasioseius ometes (Oudemans, 1903) and Hypoaspis kargi Costa, 1968 was observed using continuous video-monitoring. The process in both species was found to consist of four distinct phases. In Phase 1, both species engage in pre-ovipositional activity prior to the egg being extruded from the genital opening. In L. ometes, the female often selects a substrate depression for egg laying and examines the depression carefully with the gnathosoma and legs I before oviposition. In H. kargi, egg deposition sites are chosen without regard for substrate depressions. Phase 1 lasted approximately 3 minutes for both species. Phase 2 involved egg extrusion and holding of the egg beneath the gnathosoma. Phase 2 lasted approximately 20 times longer in L. ometes (5 minutes) than in H. kargi. Alteration of the egg surface in the form of thorn-like outgrowths was recorded in L. ometes. Egg deposition occurs in Phase 3, and in L. ometes the egg is generally placed at the deposition site using the chelicerae. Hypoaspis kargi also uses the chelicerae for egg manipulation, but also adjusts orientation of the egg with legs I. The sticky nature of egg surface in H. kargi may provide a means for the female to effectively cover the exposed egg with a protective layer of soil particles. Egg deposition in both species occurred in less than 90 seconds. Phase 4 involves egg covering, but behaviour of the female during this last phase differs markedly between the two species. In L. ometes, the female tends to remain close to the egg, whereas in H. kargi the female moves away from the egg to search for substrate particles appropriate for its covering. The average time for Phase 4 in H. kargi was approximately four times longer (80+ minutes) than in L. ometes.     

New insights on the external features of egg capsules and embryo development in the squid Loligo vulgaris

The embryonic development of the squid Loligo vulgaris was observed from 183 egg masses collected from special devices deployed throughout Cabrera National Park (Baleares Islands, western Mediterranean Sea). Sequence alignment analysis of the cytochrome oxidase I gene revealed that all embryos belonged to L. vulgaris. In total, 549 egg capsules were examined. Viable egg capsules (n = 420) were classified into one of five maturation stages according to the primary external features. The length of the viable egg capsules varied between 40 and 170 mm, and increased with embryonic development. The non-viable capsules (n = 129) were categorized into four groups: I (Ginger root), non-viable II and III, and empty egg capsule (IV). The percentage of non-viable capsules (i.e. grades I, II and III) was 92.25%. Empty capsules accounted for 7.75% of the total non-viable egg capsules. Embryonic development was classified into a second scale of eight stages. Egg capsule stage and embryonic stage were significantly related (n = 420; p < 0.001), facilitating the determination of the embryo developmental phase based on the outward appearance of the egg capsules. The embryo development stage based on the external features of the egg capsules might constitute an innovative tool for in situ embryological data collection. This new method is neither time consuming nor invasive, and could be helpful in fishing cruises, for scuba diving visual census in natural habitats and for laboratory culture. Slight variability in the developmental embryonic stages within egg capsules from the same egg mass was identified. The origin of this asynchrony is discussed. Chronological appearance of organs was similar to that of the six loliginid species previously examined. However, some developmental changes in the timing or rate of events (heterochronies) were observed: Hoyle’s organ was formed earlier in L. vulgaris and the appearance of ventral chromatophores was slightly delayed (2 days) compared with the other species considered.     

Comparative investigation of the late embryogenesis of Leptodora kindtii (Focke, 1844) (Crustacea: Branchiopoda), with notes on types of embryonic development and larvae in Cladocera

The embryonic development of the parthenogenetic eggs of Leptodora kindtii has been investigated by observing living embryos removed from the female brood pouch. The sequence of morphological changes was analysed, as was the time at which the activity of certain organs began. The timing of these events at 20–22°C is documented. These data were compared with similar information obtained for some representatives of Ctenopoda and Anomopoda. The sequence of appearance of rudiments of organs on the ventral side of the embryos is similar in all these groups but the timing of shedding of the embryonic membranes differs. Hatching from the inner egg membranes takes place at the late metanauplius stage in Leptodora as in Ctenopoda and Cyclestherida, while in Anomopoda this stage is embryonized. The development of Leptodora is more like that of Ctenopoda than of Anomopoda. The embryos of all the above‐mentioned groups begin to grow at approximately the same morphological stage. A new scheme for the periodization of the embryogenesis of L. kindtii is proposed, which includes four well‐separated stages. Previously, the same number of developmental stages has been reported for Ctenopoda and Anomopoda. In Leptodora, as well as in Ctenopoda, the first two of these occur within the egg membranes. Cyclestheria has at least one embryonic moult and one embryonic stage more than Leptodora and other cladocerans. Embryonic stages 3 and 4 of the parthenogenetic eggs of L. kindtii represent a peculiar type of secondary larvae developing inside the female's brood pouch. The appearance of a free‐living nauplius in L. kindtii arises from its mode of hatching from the gamogenetic egg.     

Analysis of VCR images of pre-oviposition and oviposition behaviour of Culex quinquefasciatus (Diptera: Culicidae) females,in the laboratory

The aim of this work was to study the pre-ovipostion and oviposition behaviour of gravid Culex quinquefasciatus females, under laboratory conditions. Preliminary tests showed that oviposition is initiated from the third day after bloodfeeding and occurs in the first two hours and the eighth to the tenth hour of scotophase. Image analysis showed that females presented different types of exploratory flights, and that the most common was touching the hay infusion with their hind legs, while flying. The two main oviposition behaviours observed were: (1) females that land at the container's inner wall, rub one leg against the other and walk towards the interface between the wall and hay infusion surface to lay the egg raft; (2) females that land on the hay infusion surface, keep four or six legs on the surface, and lay the egg raft. Interestingly, females that touched the hay infusion with their proboscis rejected it as an oviposition substrate.     

Reproduction,development and parental care in two direct‐developing flatworms (Platyhelminthes: Polycladida: Acotylea)

Variations in reproductive modes, egg production, and the effects of parental care on hatching success are compared between Pleioplana atomata and Imogine zebra. Pleioplana atomata transfers sperm via true copulation, whereas I. zebra dermally impregnates spermatophores onto the dorsal surface of partners. Pleioplana atomata lays up to 750 large eggs over a 6‐week period, and I. zebra individuals lay up to 1346 small eggs in 12 days. Female fecundity is positively correlated with body size in both species. Developmental time lines are temperature‐dependent, and juvenile worms hatch after 3 and 6 weeks for I. zebra and P. atomata, respectively. Covering of egg masses by the adult is observed for both species and although this parental care is not necessary for egg development or hatching, it plays a significant role in the hatching success of P. atomata. In I. zebra, parental covering of egg masses may play a role in eggshell development.     

Effects of temperature on the embryonic development and hatchling size of Betaeus emarginatus (Decapoda: Caridea: Alpheidae)

Betaeus emarginatus is an alpheid shrimp inhabiting rock pool environments characterized by strong fluctuations of ambient factors. Here we describe the embryonic development of B. emarginatus, and analyse the effects of three different temperatures (13, 15 and 20°C) on the duration of the incubation period, egg volume, and the size and morphology of newly hatched larvae. The sequence of embryonic development followed the general patterns described for decapods. Temperature affected the duration of the incubation period, which varied between 66.8 days (13°C) and 22.7 days (20°C). Independent of the thermal regime, eye pigment appeared after completing approximately 50% of the incubation time. Despite almost an identical initial egg volume in all three treatments, there was an inverse relation between temperature and final volume: eggs incubated at 13°C were substantially bigger (471.5 mm³) than those maintained at 15 (403.3 mm³) and 20°C (387.6 mm³). The size of the hatchlings increased significantly with decreasing incubation temperature. However, morphological variability of selected larval characters was generally higher at elevated temperatures. We compare the results obtained with those reported for other decapods inhabiting temperate waters, and discuss the question of why larvae of B. emarginatus incubated at higher temperatures hatch at a smaller size compared to those incubated at lower temperatures.     

Morphometry and chaetotaxy of the nymphs of Ectemnostega (Ectemnostegella) quechua (Bachmann 1961) (Insecta: Hemiptera: Heteroptera: Corixidae)

The egg and the five nymphal instars of Ectemnostega quechua are described and illustrated for the first time. The eggs of Ectemnostega have a short stalk, and the shape, size and chorionic structure differ among groups of species. The nymphal characters most useful in identifying instars I–V of Ectemnostega are: body length; number of rostrum sulcations; number of setae on inner surface of protibiotarsus; spines and setae, and spines on posteroventral surface of mesofemur and mesotibia, respectively; setae on posterodorsal surface of mesotibia and mesotarsus; spines and setae on anteroventral surface and setae on posterior surface of metatibia; swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and the grade of development of wing pads. The nymphs of E. quechua can be easily distinguished from other species of Ectemnostega by the number of spines and setae on the posteroventral surface of mesofemur.     

The preimaginal stages of Minotetrastichus frontalis (Nees) and Chrysocharis laomedon (Walker) (Hymenoptera: Eulophidae), parasitoids associated with Phyllonorycter issikii (Kumata) (Lepidoptera,Gracillariidae)

The biology and morphology of the early larval instars of Minotetrastichus frontalis (Nees) are redescribed and the morphology of the preimaginal stages of Chrysocharis laomedon (Walker) (Hymenoptera: Eulophidae) are described in detail for the first time. Both species are larval-pupal parasitoids of Phyllonorycter issikii (Lepidoptera, Gracillariidae), which is associated with Tilia sp. The female of M. frontalis lays her egg beside the host larva and the newly hatched first instar larva moves and has to find the host larva. The larva of P. issikii tries to continue its feeding but never pupates after paralysis. The female of C. laomedon lays its egg inside the cuticle of the larva of P. issikii, but the newly hatched parasitoid larva vacates the host larva and develops externally on its surface as an ectoparasitoid. Such behaviour might be facilitated by the constant temperature and humidity inside the mine. Some peculiarities of parasitoid–host relationships are described and discussed.     

The parasitoid complex and parasitoid‐induced mortality of spiders (Araneae) in a Central European woodland

The parasitoid complex of spiders was studied in three different sites of a forest and, for comparison, in open habitats in north‐western Lower Saxony (Germany). Qualitative data and, for four spider species, detailed quantitative rearing data were obtained. At least 25 parasitoids of spiders were recorded (23 species of Hymenoptera and two species of Diptera). External parasitoids of spiders were rare in the woodlands; only up to 1% of the spiders collected by hand searching and sweep netting had ectoparasitoids. During the investigation 23 parasitoid species were reared from spider egg masses, 10 of them occurring in woodlands. Two species were secondary parasitoids. Several parasitoid–host relationships were recorded for the first time. Egg masses of Floronia bucculenta were parasitized up to 5% by two species of the genus Gelis. Up to 10% of the egg masses of Linyphia hortensis were parasitized by Aclastus species. Egg masses of the spider genus Ero were parasitized by three species, causing an overall mortality of 40%. For egg masses of Agroeca spp. parasitization at some locations was up to 60%. An overview of the Central European parasitoid complex of spiders is provided.     

Population dynamics,age structure and sex ratio of the bromeliad-dwelling jumping spider,Psecas chapoda (Salticidae)

In this study, the population fluctuations, phenology and sex ratio of the bromeliad-dwelling jumping spider Psecas chapoda were investigated in an area of semi-deciduous forest in south-eastern Brazil. Psecas chapoda occurred and reproduced on Bromelia balansae (Bromeliaceae) throughout the year. The number of egg sacs increased at the beginning of the rainy season (September to December), but the population size and phenology were stable over time and correlated weakly with rainfall and temperature. The principal factor affecting the dynamics of P. chapoda was the blooming of B. balansae, which expelled spiders because of the drastic change in plant architecture. Male spiders were more frequent than females during the juvenile phase, whereas females were more frequent than males during the subadult and adult phases, suggesting a sex ratio that favoured males. The biotic and abiotic factors that influence the population dynamics and sex-dependent vulnerability determination are discussed.     

Morphology of immature stages of Bittacus choui (Mecoptera: Bittacidae) with notes on its biology

The hangingfly Bittacus choui Hua et Tan, 2007 Hua, B. Z. and Tan, J. L. 2007. A new species of Bittacus Latreille (Mecoptera,Bittacidae) from Daba Mountain in China.. Acta Zootaxon Sin., 32: 455–458.  [Google Scholar] is unique in Bittacidae for having only three instead of four larval instars. Its morphology was studied and illustrated in detail for developmental stages, including egg, larva and pupa. Ultrastructure of eggs, larval head, spiracles and prolegs are provided. The egg is spherical. A single micropyle was observed. The larva is eruciform with a pair of prominent compound eyes and a mid ocellus; the eight pairs of prolegs are unequal in length. Nine pairs of spiracles are located on the prothorax and the first eight abdominal segments respectively; the first instar larva differs from other instars in spiracle number. The somites are unusual, with rows of protuberances bearing distinct setiferous clavate setae. The anal segment terminates in a protrusile sucker. Pupae are exarate and decticous, taking the shape of the adults. The species completes one generation per year, overwintering as a mature larva. Adults emerge in the field from mid‐July to late August.     

New earthworm species of the genus Pheretima (Clitellata: Megascolecidae) from Mountain Province,Philippines

Six new species of the genus Pheretima are described from Mt. Amuyao and Mt. Lamagan, near Barlig, Mountain Province, the Philippines: Pheretima tanudanensis sp. nov., Pheretima amuyaoensis sp. nov., Pheretima salcedoi sp. nov., Pheretima lamaganensis sp. nov., Pheretima julkai sp. nov., and Pheretima barligensis sp. nov. Pheretima tanudanensis sp. nov. has spermathecal pores in 6/7, 0.18–0.22 circumference ventrally apart, copulatory bursae openings 0.21–0.22 circumference apart, intestinal origin in XVI, and non-muscular spermathecal ducts. Pheretima amuyaoensis sp. nov. and Pheretima salcedoi sp. nov. have spermathecal pores in 5/6–6/7, a condition not previously known in the genus. Pheretima amuyaoensis sp. nov. has ventral spermathecal pores 0.23–0.24 circumference apart, copulatory bursae openings 0.23 circumference apart, and the intestinal origin in XVI. Pheretima salcedoi sp. nov. has ventral spermathecal pores 0.21–0.29 circumference apart, copulatory bursae openings 0.18–0.20 circumference apart, and the intestinal origin in XV. Pheretima lamaganensis sp. nov. and Pheretima julkai sp. nov. belong to the dubia group in Sims and Easton with three pairs of spermathecal pores in 6/7–8/9. Pheretima lamaganensis sp. nov. is a small-bodied worm with more setae in VII than in XX, two pairs of spermathecae in VII, one pair of spermathecae in VIII, ventral spermathecal pores 0.27–0.28 circumference apart and copulatory bursae openings 0.21–0.22 circumference apart. Pheretima julkai sp. nov. has two pairs of spermathecae in VII, one pair of spermathecae in VIII, ventral spermathecal pores 0.20–0.23 circumference apart and copulatory bursae openings 0.18–0.20 circumference apart, typhlosole lacking. One new earthworm, Pheretima barligensis sp. nov. belongs to the darnleiensis group with four pairs of spermathecal pores in 5/6–8/9, and has ventral spermathecal pores 0.16–0.22 circumference apart, copulatory bursae openings 0.19–0.22 circumference apart, an intestinal origin in XVI, and septa 8/9–9/10 present.     

A new leaf-resembling genus of bush-cricket from West Africa (Orthoptera: Tettigoniidae)

Trimusculotrema warnaki gen. et sp. nov. is described from the skin of Himantura uarank Forsskål. Trimusculotrema is distinguished from other genera in the Benedeniinae by the following combination of anatomical features: accessory sclerites and anterior hamuli small; haptor with two or three intrinsic, concentric muscle bands; haptor papillate ventrally; cirrus sac with internal seminal vesicle and spermatophore matrix reservoir; separate male and female pores opening ventrally and dorsally respectively; vagina short. On the basis of these features Benedenia micracantha Euzet and Maillard, 1967 from the skin and B. leucanthemum Euzet and Maillard, 1967 from the gills of Dasyatis marmorata Steindachner off Senegal are transferred to the new genus as Trimusculotrema micracantha comb. nov. and T. leucanthemum comb. nov. The presence of haptoral papillae, noted previously in some species of Entobdella, perhaps indicates that the new genus is more closely related to entobdellids than to benedeniids. Several living specimens of T. uarnaki had 7 (2–17) eggs in early cleavage projecting from the body, their appendages gripped in a muscular sphincter at the uterine opening. These egg bundles appear to be shed from the parasite soon after laying.     

The pre-overwintering nests and the immature stages of the hornet Vespa fumida van der Vecht (Hymenoptera: Vespidae)

The pre-overwintering nest structure and the immature stages of the hornet Vespa fumida van der Vecht are for the first time reported. All three adult forms (queen, worker and drone) are briefly described. The eggs have many micropyles concentrated at the larger end of the egg. The mature larvae can be identified by having the ecdysial sulcus obliterated ventrally; the parietal band distinctly margined ventrally on the outer side; the palate with a median patch and a pair of dorsal patches; the collar processes of the spiracle long and thick, with many branches over almost all the surface. Morphology and distribution of the different types of sensilla (setae, conical papillae, campaniform sensilla, basiconic sensilla, etc.) and the spicules are illustrated in detail. Close relationship between the Vespa affinis-group and V. fumida previously suggested by adult morphology is briefly discussed in terms of the morphology of the mature larvae.     

Female life‐history characteristics of the Mosor rock lizard,Dinarolacerta mosorensis (Kolombatović, 1886) from Montenegro (Squamata: Lacertidae)

Analysis of the female life history of the poorly studied endemic Balkan lizard species Dinarolacerta mosorensis was conducted on three population samples from Montenegro. One clutch is produced annually. Females mature at body sizes of 56–57 mm snout–vent length (SVL), attained at age 3–4 years. SVL increases with age. The average clutch size ranged from 4.3 to 5.2 eggs, and was significantly positively correlated with maternal SVL in two population samples. There were no trade‐offs between egg size/offspring size and clutch size, nor between variation in egg size/offspring size and maternal SVL. The incubation period averaged 26.5 days, while hatching success in captivity was 72%. Significant positive correlations were found between the hatchling mass and egg mass and size, and also between the hatchling total length and egg width and volume. There was a significant negative relationship between the hatchling mass and incubation duration.     

Morphology and larval development of Polydora cf. websteri (Polychaeta: Spionidae) in a tropical region of north-eastern Brazil

Polydora websteri belongs to a group of the Spionidae known as the Polydora complex, members of which are known for building tubes within the shells of mussels and for their ability to infest commercially valuable bivalves, which causes serious losses for malacoculture. P. websteri is a species subjected to increasing research due to the global scale at which these infestations occur. In this paper, we describe the larval development of P.cf. websteri associated with the oyster Crassostrea cf. brasiliana in a tropical region of north-east Brazil. The main structures of all stages of development were analysed and compared to other populations of P. websteri. Ovigerous capsules of P.cf. websteri were cultured in the laboratory and the larval stages were analysed until metamorphosis. Ovigerous capsules were present in all sampling intervals, indicating that this population exhibits continuous reproduction. Up to 21 capsules per tube were found, and the number of eggs per capsule varied from 20 to 40. All observed eggs developed into larvae. Larval development from egg to recruitment stage did not exceed 13 days. Metamorphosis occurred when larvae attained 17 chaetigers, at which stage important diagnostic characteristics were revealed, such as the spines on chaetiger 5. The developmental stages of P.cf. websteri larvae, and the morphological features found at each stage, are in accordance with what has been recorded for temperate populations. In our study, the planktonic stage was found to be of shorter duration than elsewhere, which might be associated with the higher temperatures at which larvae were cultured compared to previous studies.     

Oviposition site preference and reproductive ecology of Teratohyla midas (Anura: Centrolenidae) in the Colombian Amazon

ABSTRACT

The family Centrolenidae (Glass frogs) includes 157 species of anurans with a Neotropical distribution. Although glass frogs have been the subject of several studies encompassing various aspects of their biology, natural history data on their reproductive ecology is still scarce. One of the important aspects of reproductive ecology is the oviposition site since it can impact the reproductive success of a species. Herein, we provide detailed information on the reproductive ecology of a population of Teratohyla midas from the Colombian Amazon foothills and test whether this species shows a preference on substrate and height of oviposition site. We monitored a population using capture-mark-recapture of individuals identified by a photograph of their unique pattern of dorsal yellow spots. Wild-ID Software was used to corroborate if the dorsal pattern was different between individuals. Additionally, we monitored the presence of egg clutches, amplexus and oviposition behaviour. We observed 110 males and 5 females of T. midas, seen at an average height of 3.1 m ± 2.9 (0–17.8 m) from the ground. Likewise, we recorded the amplexus behaviour of two pairs for approximately 150 min. Once the oviposition happened, the male retreated, and the female covered the egg clutches for approximately 60 min. We observed 25 egg clutches with 60% being deposited in leaves of Selaginella sp and found at an average height of 2.9 ± 1.7 m (1.1–7.0 m). Thus, the selection of oviposition site was not random but mostly specific to one type of substrate. Furthermore, there was an overlap of the re-sampled median height distributions of active individuals and clutches, which suggests that oviposition does not occur at a preferred height within the vertical distribution of individuals. The information presented here is the first detailed record of reproductive ecology for this species and we hope to provide a basis to improve our knowledge on the biology of this species and other glass frogs.