Differences in dietary and plasma fatty acids between wild and captive populations of a rare reptile, the tuatara (Sphenodon punctatus)

Tuatara (Sphenodon) are rare reptiles endemic to New Zealand. Wild tuatara on Stephens Island (study population) prey on insects as well as the eggs and chicks of a small nesting seabird, the fairy prion (Pachyptila turtur). Tuatara in captivity (zoos) are fed diets containing different insects and lacking seabirds. We compared the fatty acid composition of major dietary items and plasma of wild and captive tuatara. Fairy prions (eaten by tuatara in the wild) were rich in C20 and C22 polyunsaturated fatty acids (PUFA), especially the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In contrast, items from the diet of captive tuatara contained no C20 and C22 PUFA and were higher in medium-chain and less unsaturated fatty acids. Plasma from wild tuatara was higher in n-3 PUFA [including alpha-linoleic acid (C18:3n-3), EPA and DHA], and generally lower in oleic acid (C18:1) and palmitic acid (C16:0), than plasma from captive tuatara in the various fractions (phospholipid, triacylglycerol, cholesterol ester and free fatty acids). Plasma from wild adult tuatara showed strong seasonal variation in fatty acid composition, reflecting seasonal consumption of fairy prions. Differences in the composition of diets and plasma between wild and captive tuatara may have consequences for growth and reproduction in captivity. Accepted: 3 August 1998     

Focusing and accommodation in tuatara (Sphenodon punctatus)

Summary Photorefraction and photokeratometry were performed on two juvenile tuatara (Sphenodon punctatus, 7 years of age, total length approx. 27 cm). Sphenodon is the only surviving genus of the Rhynchocephalia, an order of reptiles. Both existing species are endangered and are found only in New Zealand. Even though Walls (1942) has stated that the ciliary muscle is relatively weak in tuataras, we observed 8 D of accommodation. The eyes were found to focus independently and we could induce an anisometropia of 6 D. The average corneal power of the tuatara was found to be 101 D.     

Seasonal and spatial dynamics of ectoparasite infestation of a threatened reptile, the tuatara (Sphenodon punctatus)

Abstract The conservation of threatened vertebrate species and their threatened parasites requires an understanding of the factors influencing their distribution and dynamics. This is particularly important for species maintained in conservation reserves at high densities, where increased contact among hosts could lead to increased rates of parasitism. The tuatara (Sphenodon punctatus) (Reptilia: Sphenodontia) is a threatened reptile that persists at high densities in forests (～ 2700 tuatara/ha) and lower densities in pastures and shrubland (< 200 tuatara/ha) on Stephens Island, New Zealand. We investigated the lifecycles and seasonal dynamics of infestation of two ectoparasites (the tuatara tick, Amblyomma sphenodonti, and trombiculid mites, Neotrombicula sp.) in a mark‐recapture study in three forest study plots from November 2004 to March 2007, and compared infestation levels among habitat types in March 2006. Tick loads were lowest over summer and peaked from late autumn (May) until early spring (September). Mating and engorgement of female ticks was highest over spring, and larval tick loads subsequently increased in early autumn (March). Nymphal tick loads increased in September, and adult tick loads increased in May. Our findings suggest the tuatara tick has a 2‐ or 3‐year lifecycle. Mite loads were highest over summer and autumn, and peaked in March. Prevalences (proportion of hosts infected) and densities (estimated number of parasites per hectare) of ticks were similar among habitats, but tick loads (parasites per host) were higher in pastures than in forests and shrub. The prevalence and density of mites was higher in forests than in pasture or shrub, but mite loads were similar among habitats. We suggest that a higher density of tuatara in forests may reduce the ectoparasite loads of individuals through a dilution effect. Understanding host–parasite dynamics will help in the conservation management of both the host and its parasites.     

Activity pattern and thermal biology of a day-flying hawkmoth (Macroglossum stellatarum) under Mediterranean summer conditions

Abstract.

• 1 The daily activity pattern and aspects of the thermal biology are described for the day-flying hawkmoth, Macroglossum stellatarum L. (Lepidoptera: Sphingidae), while foraging at a flowering population of Lavandula latifolia (Labiatae) under the dry-hot summer conditions of a southeastern Spanish locality.
• 2 The average abundance of M.stellatarum remained fairly constant from sunrise to about 17.00 hours (GMT), and a distinct peak occurred in the evening (18.00—20.00 hours).
• 3 Foraging took place over a broad range of microclimatic conditions, as described by air temperature (T_a; range 19-36°C) and solar radiation (IR; range 1–1025 Wm^-2).
• 4 The thoracic temperature (T_th) of insects remained within relatively narrow limits (39–46°C), with the highest values occurring around noon. Variation in T_th mainly reflected differences in T_a between foraging sites and times. T_th was nonlinearly related to T_a, the rate of increase of T_th with T_a decreasing with increasing T_a.
• 5 The unusual tolerance of high T_th exhibited by M.stellatarum, and its enhanced thermoregulatory capacity at high T_a, enable this species to withstand the severe environmental conditions faced during diurnal foraging in the Mediterranean summer.

     

Plasma corticosterone concentrations in wild and captive juvenile tuatara (Sphenodon punctatus)

Abstract

High mortality and abnormal growth patterns commonly found in captive juvenile tuatara were hypothesised to be due in part to the effects of long‐term chronic stress of captivity. This study compared plasma concentrations of the reptilian adrenal steroid, corticosterone, in wild juvenile tuatara on Stephens Island, Cook Strait, and in captive juveniles of Stephens Island origin, held in New Zealand institutions, in February and August 1992. Seasonal variation in plasma concentration of corticosterone in wild juveniles in four seasons of the year was also examined. This is the first study of seasonal cycles in plasma corticosterone in a wild juvenile reptile. Plasma corticosterone concentrations were significantly higher in captive juvenile females (4.21 ± 0.27 ng/ml; mean ± SE) compared with wild juvenile females (2.44 ± 0.42 ng/ml) in February (P < 0.05), but not in August, and there was no difference in concentration between captive and wild juvenile males in either month. There was significant seasonal variation in plasma corticosterone in wild juvenile females (P < 0.05). However, there was no seasonal variation observed in wild juvenile males, and the magnitude of the variation in plasma corticosterone was low in both sexes (1.28 ± 0 ng/ml ‐4.65 ±3.41 ng/ml). Although mean plasma corticosterone was higher in captive juvenile females compared with wild juvenile females in February 1992, the value in captive females was within the range of mean plasma corticosterone concentrations observed in the seasonal study, and may be therefore due to asynchronicity of seasonal cycles, rather than stress. Further research is required; however, lack of correlation between plasma corticosterone concentrations and either growth rate or density indicate that captive juvenile tuatara in New Zealand are not suffering from pronounced chronic stress.     

Effects of activity pattern on eye size and orbital aperture size in primates

Among primates, nocturnal species exhibit relatively larger orbital apertures than diurnal species. Most researchers have considered this disparity in orbital aperture size to reflect differences in eye size, with nocturnal primates having relatively large eyes in order to maximize visual sensitivity. Presumed changes in eye size due to shifts in activity pattern are an integral part of theoretical explanations for many derived features of anthropoids, including highly convergent orbits and a postorbital septum. Here I show that despite clear differences in relative orbital aperture size, many diurnal and nocturnal primates do not differ in relative eye size. Among nocturnal primates, relative eye size is influenced by diet. Nocturnal visual predators (e.g., Tarsius, Loris, and Galago moholi) tend to have larger relative eye sizes than diurnal primates. By contrast, nocturnal frugivores (e.g., Perodicticus, Nycticebus, and Cheirogaleus) have relative eye sizes that are comparable to those of diurnal primates. Although some variation in orbital aperture size can be attributed to variation in eye size, both cornea size and orbit orientation also exert a strong influence on orbital aperture size. These findings argue for caution in the use of relative orbital aperture size as an indicator of activity pattern in fossil primates. These findings further suggest that existing scenarios for the evolution of unique orbital morphologies in anthropoids must be modified to reflect the importance of ecological variables other than activity pattern.     

Microsatellite DNA loci identify individuals and provide no evidence for multiple paternity in wild tuatara (Sphenodon: Reptilia)

Six new microsatellite DNA loci are isolated from a genomic library of the sphenodontid reptile tuatara (Sphenodon) and presented here as a tool for identifying individuals for future paternity and kinship studies. These loci, in combination with four previously published loci, are sufficient to discriminate between clutch-mate siblings from Stephens Island and Brothers Island populations. These populations represent high and low levels of genetic diversity in tuatara populations respectively. An estimate of minimum number of fathers of each clutch found no evidence for multiple paternity in any clutch. These newly isolated loci complete the development of an array of genetic tools for use in tuatara to enhance ongoing conservation and management of wild, translocated and captive populations.     

Mastication in the tuatara,Sphenodon punctatus (reptilia: Rhynchocephalia): Structure and activity of the motor system

The masticatory pattern of Sphenodon punctatus, the sole remaining rhynchocephalian, now restricted to islands off the coast of New Zealand, has been analyzed by detailed anatomy, cinematography, cinefluoroscopy, and electromyography. Food reduction consists of a closing, crushing bite followed by a propalineal sliding of the dentary row between the maxillary and palatine ones. The large, fleshy tongue can be protruded to pick up small prey, and also plays a major role in prey manipulation. The rotational closing movement of the jaw, supporting the basic crushing movement, is induced by the main adductor musculature. It is followed by a propalineal anterior displacement relying heavily on the action of the M. pterygoideus. The fiber lengths of the several muscles reflect the extent of shortening. The most obvious modification appears in the M. pterygoideus, which contains a central slip of pinnately arranged short fibers that act a period different from that of the rest of the muscle; their action increases the power during the terminal portion of the propalineal phase. This also allows the animal to use its short teeth in an effective shearing bite that cuts fragments off large prey. The action of single cusped dentary teeth acting between the maxillary and palatine tooth rows provides a translational crushing-cutting action that may be an analog of the mammalian molar pattern. However, this strictly fore-aft slide does not incorporate capacity for later development of lateral movement.     

栖息地质量对黑叶猴活动时间分配的影响

2005 年9 月至2006 年8 月,在广西弄岗国家级自然保护区和扶绥珍贵动物保护区各选择一群黑叶猴作为研究对象,采用瞬时扫描取样法收集相关的行为数据。通过比较两个地理种群活动时间分配的数据来探讨栖息地质量对黑叶猴活动时间分配的影响。结果表明:生活在低质量栖息生境的黑叶猴猴群较生活在高质量栖息生境的猴群花费更多的时间休息和觅食,而用于移动和社会活动的时间相应减少。分析表明,栖息地质量的差异所造成的食物可获得性以及食物组成的差异可能是影响黑叶猴群活动时间分配差异的重要因素。虽然不同活动的峰值在日活动节律中出现的时间存在差异,但总的日活动节律在不同地理种群中表现出相同的趋势,即早晨和下午出现两个明显的觅食高峰,而中午则是长时间的休息;移动的高峰通常发生在觅食高峰之前。     

Bimodal distribution of flowering time in a natural hybrid population of daylily (Hemerocallis fulva) and nightlily (Hemerocallis citrina)

Time of flower anthesis in a day is thought to evolve in response to the time of pollinator activities. We studied blooming and withering time in natural populations of daylily (Hemerocallis fulva), nightlily (Hemerocallis citrina) and their hybrids, and also in an artificially obtained array of the F1 hybrids. Blooming time of H. fulva varied from 4:30 to 7:30 and H. citrina varied from 16:30 to 20:30. In a natural hybrid population, blooming time and withering time showed discontinuous bimodal distribution in spite that morphological traits of flowers showed continuous unimodal variation. Most F1 hybrids showed diurnal flowering. These findings indicate that only a few genes have strong phenotypic effect on the determination of flowering time in Hemerocallis, and suggest that the evolution from a H. fulva-like ancestor to H. citrina was not a continuous process by accumulation of minute mutations.     

Tooth and cranial disparity in the fossil relatives of Sphenodon (Rhynchocephalia) dispute the persistent ‘living fossil’ label

The tuatara (Sphenodon punctatus) is the only living representative of Rhynchocephalia, a group of small vertebrates that originated about 250 million years ago. The tuatara has been referred to as a living fossil; however, the group to which it belongs included a much greater diversity of forms in the Mesozoic. We explore the morphological diversity of Rhynchocephalia and stem lepidosaur relatives (Sphenodon plus 13 fossil relatives) by employing a combination of geometric morphometrics and comparative methods. Geometric morphometrics is used to explore cranium size and shape at interspecific scale, while comparative methods are employed to test association between skull shape and size and tooth number after taking phylogeny into account. Two phylogenetic topologies have been considered to generate a phylomorphospace and quantify the phylogenetic signal in skull shape data, the ancestral state reconstruction as well as morphological disparity using disparity through time plots (DTT). Rhynchocephalia exhibit a significant phylogenetic signal in skull shape that compares well with that computed for other extinct vertebrate groups. A consistent form of allometry has little impact on skull shape evolution while the number of teeth significantly correlates with skull shape also after taking phylogeny into account. The ancestral state reconstruction demonstrates a dramatic shape difference between the skull of Sphenodon and its much larger Cretaceous relative Priosphenodon. Additionally, DTT demonstrates that skull shape disparity is higher between rather than within clades while the opposite applies to skull size and number of teeth. These results were not altered by the use of competing phylogenic hypotheses. Rhynchocephalia evolved as a morphologically diverse group with a dramatic radiation in the Late Triassic and Early Jurassic about 200 million years ago. Differences in size are not marked between species whereas changes in number of teeth are associated with co‐ordinated shape changes in the skull to accommodate larger masticatory muscles. These results show that the tuatara is not the product of evolutionary stasis but that it represents the only survivor of a diverse Mesozoic radiation whose subsequent decline remains to be explained.     

Assessment of largemouth bass (<Emphasis Type="Italic">Micropterus salmoides</Emphasis>) behaviour and activity at multiple spatial and temporal scales utilizing a whole-lake telemetry array

A whole-lake acoustic telemetry array was utilized to monitor the three-dimensional position of 20 largemouth bass (Micropterus salmoides). Code division multiple access (CDMA) technology enabled the simultaneous monitoring of the 20 transmitters (equipped with pressure and temperature sensors) at 15 s intervals with sub-meter accuracy. Fish were monitored between November 2003 and April 2004 to evaluate the behaviour of fish across different temporal and spatial scales. The distance moved by largemouth bass, assessed both on a daily and hourly basis, varied by season and was positively correlated with water temperature. For example, daily movement rates were 2.69 ± 1.45 km/day in mid November (average daily water temperature 5.9°C), 2.24 ± 0.73 km/day in early January (5.1°C), and 7.28 ± 2.62 km/day in mid April (7.7°C). Interestingly, daily movement rates varied by as much as 25 fold among individual fish. Visualization of fish swimming paths revealed that whereas some fish occupied discrete areas and made only localized movements, other individuals made lengthier journeys covering much of the lake in periods of as little as one day. Analysis of fish behaviour at a finer temporal scale revealed that during the winter, fish spend more than 95% of their time swimming at speeds less than 0.1 m/s (0.07 ± 0.24 m/s). During late fall, and especially in spring, swimming speeds were higher with mean swimming speeds of 0.11 ± 0.27 m/s and 0.19 ± 0.29 m/s, respectively. When the telemetry dataset was queried to simulate 24 h manual tracking intervals, it was clear that manual tracking data would not have been representative of actual daily movement rates, underestimating daily movement and swimming speeds by at least 75 fold. This study identifies the importance of evaluating fish activity at multiple spatial (whole lake to sub-meter position) and temporal (seasonal to seconds) scales and illustrates the potential of CDMA telemetry to yield such data.     

Thermal tolerance in the Andean toad Rhinella spinulosa (Anura: Bufonidae) at three sites located along a latitudinal gradient in Chile

Rhinella spinulosa is one of the anuran species with the greatest presence in Chile. This species mainly inhabits mountain habitats and is distributed latitudinally along the western slope of the Andes Range. These habitats undergo great temperature fluctuations, exerting pressure on the amphibian. To identify the physiological strategies and thermal behavior of this species, we analyzed the temperature variables CT_min, CT_max, TTR, τ_heat, and τ_cool in individuals of three sites from a latitudinal gradient (22°S to 37°S). The amphibians were acclimated to 10 °C and 20 °C and fed ad libitum. The results indicate that the species has a high thermal tolerance range, with a mean of 38.14±1.34 °C, a critical thermal maxima of 34.6–41.4 °C, and a critical thermal minima of 2.6–0.8 °C, classifying the species as eurythermic. Furthermore, there were significant differences in CT_máx and TTR only in the northern site. The differences in thermal time constants between sites are due to the effects of size and body mass. For example, those from the central site had larger size and greater thermal inertia; therefore, they warmed and cooled in a slower manner.The wide thermal limits determined in R. spinulosa confirm that it is a thermo-generalist species, a characteristic that allows the species to survive in adverse microclimatic conditions. The level of plasticity in critical temperatures seems ecologically relevant and supports the acclimatization of thermal limits as an important factor for ectothermic animals to adapt to climate change.     

圈养獐春夏季昼间行为时间分配及活动节律

2008 年3 ～7 月,在上海市浦东新区华夏公园进行獐重引入试点,采用瞬时扫描取样法和全事件记录法,对圈养条件下24 只獐(12 雌,12 雄)春夏季昼间行为时间分配及活动节律进行了观察。结果表明:休息是春夏季最主要的行为方式,其次是摄食和运动。獐的昼间行为具有明显的节律性,以晨昏活动为主,主要活动时间集中在06:00 ～08:00 和16:00 ～18:00。单因素方差分析(One-way ANOVA analysis)和Mann-Whitney U 检验表明,在时间分配上,春、夏季休息、站立、排遗、梳理和运动行为差异极显著;雌雄间休息、站立、反刍、梳理和警戒行为差异极显著。雌性春、夏季站立、排遗、梳理、运动和社会行为差异极显著,摄食差异显著;雄性春、夏季休息、摄食、梳理、警戒和社会行为差异极显著,站立、反刍、排遗和运动行为差异显著。本研究结果表明重引入獐的行为时间分配和活动节律与野生种群相似,动物福利得到较好满足,对下一步在上海地区的种群复壮和迁地野放等具有重要意义。     

Social network structure and parasite infection patterns in a territorial reptile, the tuatara (Sphenodon punctatus)

We investigated whether the parasite load of an individual could be predicted by its position in a social network. Specifically, we derived social networks in a solitary, territorial reptile (the tuatara, Sphenodon punctatus), with links based on the sharing of space, not necessarily synchronously, in overlapping territories. Tuatara are infected by ectoparasitic ticks (Amblyomma sphenodonti), mites (Neotrombicula spp.) and a blood parasite (Hepatozoon tuatarae) which is transmitted by the tick. We recorded the location of individual tuatara in two study plots twice daily during the mating season (March) in 2 years (2006 and 2007) on Stephens Island, New Zealand. We constructed weighted, directed networks to represent pathways for parasite transmission, where nodes represented individual tuatara and edges connecting the nodes represented the extent of territory overlap among each pair of individuals. We considered a network-based hypothesis which predicted that the in-strength of individuals (the sum of edge weights directed towards a node) in the derived network would be positively related to their parasite load. Alternatively, if the derived social network did not reflect actual parasite transmission, we predicted other factors such as host sex, size or territory size may better explain variation in parasite infection patterns. We found clear positive relationships between the in-strength of tuatara and their tick loads, and infection patterns with tick-borne blood parasites. In particular, the extent that individuals were connected to males in the network consistently predicted tick loads of tuatara. However, mite loads of tuatara were significantly related to host sex, body size and territory size, and showed little association with network measures. The results suggest that the pathway of transmission of parasites through a population will depend on the transmission mechanism of the parasite, but that social networks provide a powerful predictive tool for some parasites.     

Recording movement and activity pattern of a White-tailed Sea Eagle ( Haliaeetus albicilla ) by a GPS datalogger

For the first time, we measured the home range size and activity pattern of a White-tailed Sea Eagle (WTSE) by GPS telemetry. Positions were recorded three times a day and the activity pattern were continuously recorded by two acceleration sensors. From July to January, we obtained 475 positions and calculated a 95% kernel home range of 4.53 km² and a 95% minimum convex polygon of 8.22 km², indicating a rather small area explained by an optimal habitat and by the much more precise location method used here compared to reports in the literature. Biorhythmic analysis of activity data revealed nearly no night-activity, high day-activity with no fixed daily pattern and a strong 24-h period of activity. The stability and synchronisation between the eagle's activity and the environmental 24-h period was evaluated by calculating the degrees of functional coupling (DFC) and the harmonic part (HP). Mostly, DFC was 100% (meaning that the different physiological and behavioural functions are completely synchronised to each other and to the environmental 24-h period) and the few incursions of the DFC we assumed to be caused by clinically relevant lead intoxications. The agonal stage of the WTSE was indicated by a daily decreasing activity level and HPs and highly modified day–night relationship, and decreasing DFCs at the beginning and at the end of dying process, representing changes in the activity structure. The underlying reason for the behavioural changes was found to be a lethal lead intoxication due to an oral ingestion of particles of rifle ammunition. The new technology of a combined GPS receiver and an acceleration sensor allows the automatic measuring of positions and activity of wild animals at a very precise level over prolonged periods which cannot be achieved by manpower.     

邦亮东黑冠长臂猿日食性与活动节律的季节性变化

日食性变化和活动节律是动物行为的重要方面,通过对日食性变化与活动节律的研究,可以了解食物、温度和光照时间等环境因素的变化对动物行为的影响,以及动物在行为上的应对策略。2009 年1 -12 月,在广西靖西县邦亮东部黑冠长臂猿自治区级自然保护区内,采用瞬时扫描取样法对2 群东黑冠长臂猿觅食行为和活动节律进行了研究。结果显示,东黑冠长臂猿的活动和食性在旱季和雨季都具有明显的节律。鸣叫只发生在12:00之前,但旱季的鸣叫时间偏晚。在日节律上,东黑冠长臂猿在离开过夜树后和进入过夜树前各有一个取食高峰,07:00 喜欢取食果实和无花果,16:00 也选择更多的果实,但无花果较少,13:00 - 15:00 取食更多的叶和芽。在10:00 - 12:00,其用于休息和社会活动的时间增加。在雨季,东黑冠长臂猿以果实和无花果为主要食物,并且花大量时间觅食无脊椎动物;但在旱季,其食物以叶和芽为主。与之相适应,东黑冠长臂猿在旱季通过减少移动增加休息来节约能量开支和应对低温,同时它们增加取食的时间以获得等价的能量和营养。雨季时社会行为的比例明显高于旱季,而且其高峰出现在08:00 - 10:00,但旱季社会行为主要出现在11:00 - 14:00。在雨季东黑冠长臂猿没有出现休息高峰,相反在旱季10:00 左右出现一个明显的休息高峰。上述行为节律体现了东黑冠长臂猿对环境季节性变化的良好适应,使其能够在寒冷并且退化的喀斯特森林中生存繁衍。     

Environmental correlates of Freckled Nightjar ( Caprimulgus tristigma ) activity in a seasonal, subtropical habitat

We examined environmental correlates of activity in the Freckled Nightjar (Caprimulgus tristigma), a nocturnal aerial insectivore that is resident year-round in the colder and drier parts of southern Africa. Specifically, we tested the prediction that air temperature (T _a), in addition to light availability, is a significant correlate of Freckled Nightjar activity. We found that aerial insect density varied by over three orders of magnitude (from <1.0 to 117.1 insects 1,000 m⁻³) during the course of the study, and was strongly and positively related to T _a. Nightjar activity was also significantly temperature-dependent, with a cessation of activity at T _a < 12°C. Consistent with previous studies, we found that activity levels were strongly related to ambient light, with markedly reduced activity levels on dark nights. The average number of Freckled Nightjars encountered per 14.6-km transect was 1.95 ± 2.44 nightjars transect⁻¹ during nights near full moon, but only 0.17 ± 0.61 nightjars transect⁻¹ around new moon. Our study reveals that caprimulgid activity can be significantly influenced by temperature as well as ambient light.