The influence of light and sea water temperature on the reproductive cycle of Lineus ruber (Heteronemertea)

The cerebral ganglia of Lineus ruber secretes a neurohormone named gonad-inhibiting hormone (GIH) controlling reproduction. As L. ruber undergoes repeated annual cycles of reproduction during its life, the way the neuroendocrine activity of the worm is seasonally regulated is an important ecophysiological question. In other words, what environmental ‘key factors’ influences the beginning of spawning season in L. ruber? In the present work we show that light is not a timer which controls the annual reproductive cycle progress of L. ruber. On the other hand our results suggest that thermoperiod is a good candidate for this function. Further work is still necessary to clarify the transduction mechanism of thermal stimuli in GIH discharge.     

Biochemical sex dimorphism in Lineus lacteus

Egg-specific and sperm-specific proteins fromLineus lacteus females and males were investigated byanalytical electrophoreses. These major sex-specificproteins define the sexual dimorphism of biochemicalmetabolism and are useful for studying vitellogenesisand spermatogenesis. The major yolk proteins in theeggs of the nemertean, Lineus lacteus, wereidentified by gradient gel electrophoresis. The 2vitellin proteins were designated vitellin V1 (460 kDa) andvitellin V2 (260 kDa). The vitellins wereidentified as lipoglycoproteins by selective staining.Three major vitellin subunits (75, 41 and 40 kDa) werefound in oocytes of L. lacteus byelectrophoresis under denaturing conditions(SDS-PAGE). Polyclonal antibodies were raised to eachvitellin subunit. The binding of these rabbitantibodies to vitellins V1 and V2 showed that vitellinV1 contained a single major 75 kDa polypeptide, whilevitellin V2 had two major polypeptides (41 and 40 kDa).Five male-specific proteins (52, 50, 41, 35 and 32 kDa) wereidentified in the sperm of Lineuslacteus by gradient gel electrophoresis. Four lowmolecular weight proteins (18–13 kDa) can also be usedas molecular markers of male sexual maturation. Theseproteins were nucleosomal core histones. The chromatinof L. lacteus sperm contained onlyhistones as no protamines or protamine-like proteinswere detected. But the sperm nucleosomal protein maynot be entirely somatic-histones, as a sperm-specifichistone (Sp H) was also found.     

Nemerteans of the Great Barrier Reef 2. Anopla Heteronemertea (Baseodiscidae)

Three species of heteronemerteans from the Great Barrier Reef province of Australia are described and illustrated. These are Baseodiscus delineatus (Delle Chiaje 1825), Baseodiscus hemprichii (Ehrenberg 1831) and Baseodiscus quinauelineatus (Quoy Sc Gaimard 1833). Baseodiscus hemprichii has not previously been reported from Australia. For all three species a full list of known locations is provided.     

Ultrastructure of sperm and male reproductive system in Lineus viridis (Heteronemertea, Nemertea)

Nemerteans possess serially arranged gonads that lie between the midgut pouches. In both sexes the gonads are lined with an epithelium. During maturity, they gain contact to the exterior by a ciliated duct, which is generally assumed to be a derivative of the gonad. Gonad lining and sperm ultrastructure are little known in heteronemerteans, a group of nemerteans belonging to the Anopla, one of the two large nemertean subgroups. Reproduction biology in heteronemertean Lineus viridis allows predicting a modified sperm type, so-called introsperm for this taxon. Nothing is known on the fate of the testes at the end of the reproductive period of this perennial species. In order to test the predictions and to broaden the data base, males of L. viridis were collected at different times of the year. Histological and ultrastructural data show that the gonad wall is lined with different aciliated endothelial cells and germ cells, while the gonoduct is formed by densely ciliated cells. The testes are completely filled with sperm cells during maturity; there is no hint at ongoing spermiogenesis at this time. The sperm consists of head, midpiece and tail. Externally, head and midpiece cannot be discriminated. The acrosome is cup-shaped and lies anterior to the nucleus which contains 6–8 lateral ridges. Three long mitochondria mark the midpiece. They line the posterior section of the nucleus and extend up to the level of the ciliary basal structures. The sperm morphology corroborates the predictions derived from the mode of reproduction. At the end of the reproductive period the male gonads change cellular composition, while the gonoduct degenerates. Provided that both sexes show the same growth rate, male offspring acquire sexual maturity earlier than female offspring, since L. viridis males are always smaller than the females. In contrast to the males, females keep their gonads and gonoducts during most time of the year. Since large males were never found within the studied population, these data indicate that L. viridis might be a consecutive hermaphrodite.     

Ultrastructure and development of the rhabdomeric eyes in Lineus viridis (Heteronemertea, Nemertea)

Nemerteans are undoubtedly members of the Spiralia, although their phylogenetic relationships are still a matter of debate. The apparently acoelomate organization suggests a relationship with the platyhelminths, whereas the blood-vascular system has been interpreted as an equivalent to coelomic cavities of annelids, indicating a close relation between annelids and nemerteans. Like other spiralians, most nemertean species are known to have one or several pairs of rhabdomeric and subepidermally situated eyes when adult. The development of these eyes as well as the mode in which the eyes are multiplied is as yet unknown. This is the first attempt to investigate eye formation in a nemertean. In the heteronemertean Lineus viridis (Müller, 1774) the everse rhabdomeric eyes are located deeply underneath the epidermis and consist of a few pigment cells that form a cup-like structure with interdigitating processes that contain numerous pigment granules. In hatchlings, the optical cavity contains processes of 12 sensory cells, each bearing a single cilium and various microvilli. The perikarya of these cells are located distally from the pigment cup. During further development the number of cells increases. Eye development starts with a small anlage situated underneath the epidermis, irrespective of whether this is the first eye or any additional one. The anlage consists of five unpigmented cells and three dendritic processes, each bearing apical microvilli and a single cilium. There is no evidence for an epidermal origin of the eyes. In L. viridis eye formation resembles that described in platyhelminths in which eyes also develop as cerebral derivatives. Although this result has the potential to influence the discussion on the position of Nemertea, the data have to be interpreted with care, since development of L. viridis is derived within the Nemertea.     

Nemerteans of the Great Barrier Reef 4. Anopla Heteronemertea (Valenciniidae)

A new valenciniid heteronemertean, Valencinina albula , gen. et sp. nov. from the Great Barrier Reef province of Australia, is described and illustrated. This is the first record of a valenciniid from Australasian waters.     

Immunocytochemical localization of hydroxyindole-o-methyltransferase (HIOMT) in the brain of Myoisophagos lacteus (Nemertea: Heteronemertea: Lineidae)

In an attempt to identify the brain structures that synthesize melatonin and that probably mediate the photoperiodic response of the heteronemertean Myoisophagos lacteus, we utilized immunocytochemical techniques and employed immunoglobulins directed against hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4). This enzyme catalyzes the last step of melatonin biosynthesis. In immunocytochemically treated head sections of Myoisophagos lacteus, antibodies labelled a few cells in the dorsal region of the dorsal cerebral ganglia. Previous studies have shown that melatonin is present both in the brain and eyes of this nemertean species and that melatonin is involved in control of the worm reproduction. Other studies have demonstrated the presence of photoreceptor-like cells in the same region of the worm brain that showed HIOMT immunostaining. Therefore, anatomical findings of the present study, coupled with results of previous works, provide strong evidence that this region of the worm brain houses a photoperiodic receptor involved in melatonin biosynthesis. J. Exp. Zool. 290:156-162, 2001.     

Evaluating the utility of an accelerometer and urinary hormone analysis as indicators of estrus in a Zoo-housed koala (Phascolarctos cinereus)

Induced ovulators, such as the koala, do not always have overt signs of estrus, which makes pairing these animals for breeding purposes difficult to achieve in a zoo setting. This study examined the possibility of using alternative methods to behavioral sampling and weight fluctuations for monitoring estrus in a female koala of reproductive age. We attempt to gain an improved understanding of koala estrus and enhance our ability to detect it by combining a noninvasive technique for hormone analysis with a newer method for recording activity level. The findings suggest that activity levels were accurately measured using an accelerometer and increased activity was associated with one estrus behavior, bellowing. Weekly weight declines occur with increases in activity registered from the accelerometer. We also validated an assay to detect progesterone and estradiol in female koala urine in an attempt to detect an estrus spike. However, neither urinary concentrations of estradiol nor progesterone was associated with behavioral cues of estrus in our subject. We suggest that increased female activity, bellowing, and weight loss all indicate a pro-estrus state that requires proper male stimulation in order to achieve a full estrus display. Zoo Biol 28:59–68, 2009. ©2008 Wiley-Liss, Inc.     

Recombination indices in species of Erythrina L. (Leguminosae, Papilionoideae)

Darlington's recombination indices were calculated for eight species of Erythina by adding the mean chiasma frequency and the haploid chromosome number of each species. The recombination indices distinguished subgenus Erythraster (two species with greater mean chiasma frequency) from subgenera Micropteryx and Eythrina. This discrimination corroborates literature data on pollen morphology. It was not possible to separate groups at sectional level using recombination index. The recombination indices were also compared with data on breeding system and pollinators, available in literature, to investigate Grant's hypothesis on the occurrence of compensatory mechanisms in the regulation of recombination in plants. The data on breeding systems in Eythrina are very incomplete and it was not possible to correlate values of recombination indices with autogamy or allogamy. Species visited by hummingbirds showed lower recombination indices than species visited by other kind of pollinators.     

The Association of Intergroup Encounters,Dominance Status,and Fecal Androgen and Glucocorticoid Profiles in Wild Male White‐Faced Capuchins (Cebus capucinus)

Androgens play a role in male reproductive competition, frequently via aggression, while glucocorticoids are associated with the stress response. However, the relationships of these hormones with different sources of competition (intra‐ vs. intergroup) and dominance status are highly variable. Here, we consider the fecal androgen (fA) and glucocorticoid (fGC) profiles of alpha and subordinate male Cebus capucinus in the context of intergroup competition during a rare period of low intragroup competition (i.e. all females were either pregnant or lactating). Intergroup encounters (IGEs) are a long‐term reproductive strategy in male white‐faced capuchins, enabling them to assess the composition of neighboring groups. IGEs pose a threat to resident males as these can result in injury or death, loss of dominance rank, group eviction, and group takeovers that are frequently associated with infanticide. From February to July 2007, fecal samples were collected from eight males in three groups of white‐faced capuchins in the Santa Rosa Sector of the Área de Conservación Guanacaste, Costa Rica. IGE rate was positively associated with both fA and fGC levels, indicating that IGEs are perceived as reproductive challenges by resident males, and may be associated with elevated metabolic costs. Alpha males sire the majority of group offspring and, accordingly, the threat of IGEs to both future (via rank loss or eviction) and current (via infanticide) reproductive success is greater than for subordinate males. Consistent with this observation, alpha males had higher fA and fGC levels than subordinate males. Given that all females were either pregnant or lactating and pronounced overt intragroup competition was absent, we interpret the difference in hormone profiles of alpha and subordinate males as being primarily associated with variation in the perceived threats of IGEs according to dominance status. Future studies should focus on the interaction of intra‐ and intergroup competition by examining hormone levels in the presence of periovulatory females. Am. J. Primatol. 75:107‐115, 2013. © 2012 Wiley Periodicals, Inc.     

Failure of the prostaglandin F2 alpha analogue, cloprostenol, to induce functional luteolysis in the olive baboon (Papio cynocephalus anubis)

The prostaglandin F2 alpha analogue, cloprostenol, which is an effective luteolytic agent in the common marmoset, was administered intramuscularly to olive baboons to determine if it possessed luteolytic properties in this species. The results showed that functional luteolysis was not induced when cloprostenol was administered during the mid- to late luteal phase or during early pregnancy.     

大血藤生殖生物学研究

通过野外观测、实验室分析以及人工套袋授粉等方法,研究了大血藤的繁育系统、开花习性、传粉方式以及花粉-胚珠比等生殖生物学特征.结果表明,大血藤的花为单性花,雌雄同株.雄花单花花期为7~10 d,雌花单花花期为2~3 d,种群开花历时14~17 d,散粉高峰期为4月11~17日,属风媒传粉植物.大血藤花粉-胚珠比为600±20,属兼性异交类型,人工套袋实验进一步证明,大血藤的交配系统为兼性异交类型,但以异交为主.     

Delayed autonomous self‐pollination in two Japanese varieties of Epipactis helleborine (Orchidaceae)

The terrestrial orchid Epipactis helleborine is a morphologically variable species with a wide geographical distribution. It is found throughout Europe and continues eastwards to Siberia, China and Japan. It is usually pollinated by social wasps and displays the morphological characteristics of an outcrossing species. In warm, temperate areas of Japan, E. helleborine often appears in alpine or subalpine regions, and has never been found in low‐altitude forests, except for coastal pine forests. The coastal population of E. helleborine is often classified at the variety level, as E. helleborine var. sayekiana, and the inland populations are known as E. helleborine var. papillosa. It is possible that E. helleborine var. sayekiana possesses a distinctive selfing strategy, as its autonomous self‐pollination has evolved in dry habitats, such as coastal dunes. The present study investigated the pollination biology of E. helleborine var. sayekiana and var. papillosa to detect differences in their reproductive systems. Unexpectedly, both E. helleborine var. papillosa and E. helleborine var. sayekiana were found to possess a self‐pollination strategy and were therefore rarely visited by insects. Self‐pollination occurs at the end of the flowering season and probably acts to ensure pollination even if insect‐mediated pollination fails. Moreover, there are no floral differences between E. helleborine var. papillosa and E. helleborine var. sayekiana. These observations suggest that it is not necessary to distinguish between these two varieties. Furthermore, E. helleborine var. papillosa was pollinated by hoverflies, suggesting that E. helleborine var. papillosa is probably biologically distinct from its mother species, E. helleborine. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 733–743.     

Biotic versus abiotic pollination in Oeceoclades maculata (Lindl.) Lindl. (Orchidaceae)

Geographical variation in the reproductive biology of widespread species often occurs at their distributional boundaries. We sought to determine whether such variation has occurred in an invasive orchid, Oeceoclades maculata, across its naturalized range. We compared its reproductive biology in a Brazilian population with that published for a population on the Caribbean island of Puerto Rico. In the state of São Paulo, O. maculata flowers between December and February, at the height of the rainy season. Similar fruit sets were observed in manual self (76%) and cross (70.4%) pollination treatments. The fruit set of plants protected from both pollinators and rainfall was 6.1%, whereas plants exposed only to rainfall had a fruit set of 41.4%, slightly less than the controls (48.3%). Like the Puerto Rico population, reproduction is primarily through rain‐assisted autogamy, but unlike observations made on the island, outcrossing can eventually occur. We observed two butterfly species (Heliconius ethilla narcaea and Heliconius erato phyllis) pollinating O. maculata. Secretory epidermal cells and trichomes of the spur lumen produced 0.7 µL of 25% (sucrose equivalents) nectar per flower each morning, which was stored in a dilated basal portion of the spur and reabsorbed by the afternoon. Thus, geographical variation in reproductive biology exists across the broad invasive range of O. maculata.     

Endocrine control of reproduction in two rhynchocoelan worms

This brief review of the reproductive endocrinology in two distant species of Rhynchocoela examines selected results of earlier studies on the heteronemertean, Lineus ruber, and reports current and unpublished research on the hoplonemertean, Amphiporus lactifloreus.

Experimental evidence is presented for existence in the brain of a gonad-inhibiting hormone (GIH) that controls reproduction in male and female worms of both species. In adults deprived of GIH during the quiescent phase of the reproductive cycle, sexual characteristics grow rapidly and precociously; GIH replacement therapy prevents the anticipated sexual development. In L. ruber, the removal of GIH stimulates macromolecular syntheses in sexual target cells of both sexes: RNA synthesis is promoted in young oocytes; DNA synthesis is increased in spermatogonia, and induced in primary spermatocytes; and protein synthesis is significantly increased in gametocytes and sex-specific skin glands. GIH might be a regulating hormone which would inhibit the secretion of sex-specific stimulating substances produced by cells in proximity to the gonads.     

Behavioral and endocrine correlates of reproductive failure in social aggregations of captive wolverines (Gulo gulo)

Sociality in mammals is often viewed as a dichotomy, with sociality contrasted against solitariness. However, variation within these broad categories may have strong effects on individual fitness. For example, reproductive suppression of social subordinates is generally associated with group living, but suppression may also occur in solitary species if the behavioral and physiological processes involved can be modulated by the demographic environment. To investigate whether behavioral and physiological traits that normally are associated with group living might be latent even in a solitary species, we explored the level of sociality and investigated causes and mechanisms of reproductive failure in female wolverines Gulo gulo that experienced a highly aggregated social environment in captivity. Behaviorally, females showed low levels of aggression and intermediate levels of social interactions. Reproductive failure seemed to have been related to low social rank and to have occurred between ovulation and implantation in 13 out of 15 breeding attempts. However, three of eight females observed to mate produced offspring, indicating that no individual female fully managed to monopolize breeding. Reproductive failure was not related to elevated levels of glucocorticoid stress hormones. Rather, elevated glucocorticoid levels during the mating season were associated with successful reproduction. We suggest that social tendencies and physiological mechanisms mediating reproductive suppression may be viewed as reaction norms to the social environment. We further suggest that the social flexibility of solitary carnivores might be greater than is commonly observed, due to ecological constraints that may limit aggregation.     

Nemerteans of the genus <Emphasis Type="Italic">Ototyphlonemertes</Emphasis> (Enopla: Ototyphlonemertidae) from Van Phong Bay (South Vietnam)

Two species of the interstitial nemerteans from the intertidal zone of Van Phong Bay (southern Vietnam) are described. By the structure of the proboscis and statocysts, the nemertean Ototyphlonemertes ani sp. n. can be referred to the species group “Lactea” (sensu Envall, Norenburg, 2001), but it differs from other species of this group by the presence of cerebral organs and caudal cirri. The second species new for the region is very similar to O. martynovi, but differs from it in having 2 to 3 cephalic cirri in group C (instead of 4 to 6 cirri found in O. martynovi).     

Longitudinal monitoring of fecal testosterone in male Malayan Sun bears (U. malayanus)

Fecal steroid monitoring was applied as a non‐invasive method to investigate testicular cycles and seasonality in the Malayan Sun bear (Ursus malayanus), an endangered ursid from South East Asia. Fecal testosterone was analyzed by radioimmunoassay in samples collected from male Sun bears (n=8) housed in zoological parks in North America and New Zealand, over periods of <27 months. Testosterone levels were often, but not exclusively, elevated during mating periods with peaks accompanying breeding behavior and copulation. There was a significant effect of age with older bears having clearly higher concentrations of fecal testosterone (P<0.001). Testosterone concentrations fluctuated throughout the year, with no significant effect of season (P>0.05). All bears did, however, share a common pattern of annual excretion that suggests a potential role for non‐photoperiodic seasonal influences on testicular cycles. Levels were generally lower early in the year with regular increases occurring at 3–4‐month intervals. Grouped data suggest an association between cycles of testosterone production in males and months of peak reproductive activity in captivity. Zoo Biol 0:1–15, 2005. © 2005 Wiley‐Liss, Inc.     

Larval development of nemerteans of the genus Quasitetrastemma (Nemertea: Monostilifera)

Data on the larval development of Quasitetrastemma stimpsoni and Q. nigrifrons are presented. In both species, fertilization is external; the development passes through a free-swimming larval stage, the “hidden larva.” The larva has three pairs of eyes. After settling, the eyes of the second pair fuse with eyes of the first pair or are completely reduced. The basis and stylets are formed in 7–8 days after fertilization. Larvae of Q. stimpsoni settle on day 9–10 after fertilization; and Q. nigrifrons, on day 7–8.