Climate-induced reaction norms for life-history traits in pythons

Climate change modelers predict increasingly frequent “extreme events,” so it is critical to quantify whether organismal responses (such as reproductive output) measured over the range of usual climatic conditions can predict responses under more extreme conditions. In a 20-year field study on water pythons (Liasis fuscus), we quantified the effects of climatically driven annual variation in food supply on demographic traits of female pythons (feeding rate, body size, body mass, and reproductive output). Reaction norms linking food supply to feeding rates and residual body mass were broadly linear, whereas norms linking food supply to female body size became curvilinear when a dramatic (flooding-induced) famine reduced the mean body size at sexual maturity. Thus, the reaction norms recorded over 16 years of “normal” (albeit highly variable) climatic conditions gave little insight into the population's response to a more extreme nutritional crisis.

Do natural antibodies compensate for humoral immunosenescence in tropical pythons?

Ageing is frequently claimed to result in an age-dependent deterioration in immune function. Our results, however, based on 30 known-aged water pythons (Liasis fuscus; age ranging from <1 to 18 years) immunized with keyhole limpet haemocyanin (KLH), demonstrate that age-related changes in immune function may follow different and opposing pathways. Python-specific humoral antibodies (SpAb) showed an age-dependent decrease in cross-reactivity to KLH, whereas natural antibodies (NAbs) ability to bind to this antigen increased with age. Notably, when humoral SpAb and NAb titres were combined, no effect of age was detected in antibody cross-reactivity, strongly suggesting that NAbs may play a crucial role in maintaining immunocompetence during the ageing process.

How well do predators adjust to climate-mediated shifts in prey distribution? A study on Australian water pythons

Climate change can move the spatial location of resources critical for population viability, and a species' resilience to such changes will depend upon its ability to flexibly shift its activities away from no-longer-suitable sites to exploit new opportunities. Intuition suggests that vagile predators should be able to track spatial shifts in prey availability, but our data on water pythons (Liasis fuscus) in tropical Australia suggest a less encouraging scenario. These pythons undergo regular long-range (to >10 km) seasonal migrations to follow flooding-induced migrations by their prey (native dusky rats, Rattus colletti). However, when an extreme flooding event virtually eliminated rats for a three-year period, the local pythons did not disperse despite the presence of abundant rats only 8 km away; instead, many pythons starved to death. This inflexibility suggests that some vagile species that track seasonally migrating prey may do so by responding to habitat attributes that have consistently predicted prey availability over evolutionary time, rather than reacting to proximate cues that signal the presence of prey per se. A species' vulnerability to climate change will be increased by an inability to shift its activities away from historical sites toward newly favorable areas.

Short telomeres in hatching snakes : erythrocyte telomere dynamics and longevity in tropical pythons

Telomere length (TL) has been found to be associated with life span in birds and humans. However, other studies have demonstrated that TL does not affect survival among old humans. Furthermore, replicative senescence has been shown to be induced by changes in the protected status of the telomeres rather than the loss of TL. In the present study we explore whether age- and sex-specific telomere dynamics affect life span in a long-lived snake, the water python (Liasis fuscus).

Molecular and morphological description of a Hepatozoon species in reptiles and their ticks in the Northern Territory, Australia

Ticks, representing 3 species of Amblyomma, were collected from the water python (Liasis fuscus) and 3 additional reptile species in the Northern Territory, Australia, and tested for the presence of Hepatozoon sp., the most common blood parasites of snakes. In addition, blood smears were collected from 5 reptiles, including the water python, and examined for the presence of the parasite. Hepatozoon sp. DNA was detected in all tick and reptile species, with 57.7% of tick samples (n = 187) and 35.6% of blood smears (n=35) showing evidence of infection. Phylogenetic analysis of the 18S rRNA gene demonstrated that half of the sequences obtained from positive tick samples matched closest with a Hepatozoon species previously identified in the water python population. The remaining sequences were found to be more closely related to mammalian and amphibian Hepatozoon species. This study confirms that species of Amblyomma harbor DNA of the same Hepatozoon species detected in the water pythons. The detection of an additional genotype suggests the ticks may be exposed to 2 Hepatozoon species, providing further opportunity to study multiple host-vector-parasite relationships

Persistence of a threatened species in a modified alpine resort environment: the broad-toothed rat

Habitat change due to resort development threatens rare and endemic fauna of alpine and subalpine regions. There is an urgent need to understand species persistence in such areas. The broad-toothed rat (Mastacomys fuscus) is a rare, specialist species found in alpine and subalpine regions of Australia. We conducted fecal pellet surveys in an alpine resort to determine the species' distribution and habitat requirements. Eight individuals were radiotracked to investigate movement patterns and habitat use. Fecal pellets were found in areas of dense vegetation cover up to 1 m above ground. Home ranges were small (1,488-6,106 m²) and encompassed managed indigenous vegetation on or beside ski runs. Five individuals regularly crossed a narrow (3-5 m) cleared track. Two adult males dispersed (including traversing a wide grassy ski run) up to 1 km. The ability to cross modified areas and move throughout the landscape is proposed as a key factor facilitating the persistence of M. fuscus in the resort. Enhancing the capacity of species to move between habitat patches should be incorporated into alpine resort management plans. Such management will become increasingly important as anthropogenic disturbance increases in alpine regions.

Hemoparasites of the genus Trypanosoma (Kinetoplastida: Trypanosomatidae) and hemogregarines in Anurans of the São Paulo and Mato Grosso do Sul States - Brazil

Os animais silvestres estão expostos a inúmeros patógenos,dentre eles estão os hemoparasitas. Podem-se destacar espécies do gênero Trypanosoma e do grupo das hemogregarinas,que ocorrem com freqüência parasitando anuros (rãs, pererecas e sapos). Normalmente, a descrição destes hemoparasitas é feita através da morfologia dos estágios observados nosangue periférico do hospedeiro e as pesquisas sobre o ciclobiológico desses hemoparasitas são escassas. Os objetivos dopresente estudo foram avaliar a presença de hemogregarinas eTrypanosoma spp. em anuros capturados nos Estados de São Paulo e Mato Grosso do Sul e fazer a caracterização morfológica e morfométrica dos seus hemoparasitas. As espécies deanuros examinadas foram: Dendropsophus nanus, D. minutus, Leptodactylus chaquensis, L. podicipinus, L. labyrinthicus, L. fuscus, Bufo granulosus, B. schneideri, Phyllomedusahypocondrialis, Trachicephalus venulosus, Scinax fuscovarius e Hypsiboas albopunctatus. Dos 40 animais estudados, foramencontrados quatro (10%) positivos para hemogregarinas e oito(20%) positivos para Trypanosoma spp. Foram observadosgamontes de hemogregarinas com morfologia variável e, alémdas formas intraeritrocíticas, também foram observados gamontes fora das hemácias. As formas de Trypanosoma encontradas eram muito polimórficas, conforme é descrito na literatura, sendo na sua maioria, larga e oval.

First evidence of an intimate symbiotic association between fungi and larvae in basal attine ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evolution of Substrate Preparation Behaviors for Cultivation of Symbiotic Fungus in Attine Ants (Hymenoptera: Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cleaning Symbiosis Between Hawksbill Turtles and Reef Fishes at Fernando de Noronha Archipelago, off Northeast Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The taxonomic status of Leptodactylus geminus Barrio, 1973

The advertisement calls of Leptodactylus geminus, Leptodactylus gracilis, Leptodactylus plaumanni, and Leptodactylus fuscus are analyzed and compared with published reports. Based on calling data and examination of type material, Leptodactylus geminus is synonymized with L, plaumanni. To differentiate between the sibling species L. gracilis and L. plaumanni, fieldwork is needed, including recording of advertisement calls. Reliable identification of red specimens is not possible based on morphology and coloration alone.

Anuran captured in pitfall traps in three agrossystem in Northwestern São Paulo State, Brazil

Embora seja geralmente assumido que a agricultura influencia negativamente populações de anfíbios, existem poucos estudos sobre os efeitos dos cultivos agrícolas em anuros neotropicais. Visando contribuir para diminuir essa lacuna de conhecimento, no presente estudo buscamos verificar quais espécies de anuros estão presentes nos agrossistemas. Para isso, usamos dados de anuros capturados em armadilhas de queda, inicialmente proposto para o levantamento da fauna de opiliões em três agrossistemas (milho, soja e seringal). Nós registramos quatro espécies de anuros nas armadilhas de queda: Leptodactulus fuscus, L. mystacinus (Leptodactylidae), Eupemphix nattereri e Physalaemus cuvieri (Leiuperidae). Na plantação de milho foram registradas quatro espécies e 30 indivíduos, no seringal quatro espécies e 11 indivíduos e na plantação de soja três espécies e oito indivíduos. Nossos resultados mostram que os anuros estão presentes nos agrossistemas, principalmente espécies de anuros generalistas.

Diets of tadpoles from a temporary pond in southeastern Brazil (Amphibia, Anura)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Torpor in three species of Brazilian hummingbirds under semi-natural conditions

We measured body temperatures in three species of Brazilian hummingbirds, the Versicolored Emerald (Amazilia versicolor; body mass 4.1 g), the Black Jacobin (Me lantrochilus fuscus; body mass 7.7 g) and the Swallow-tailed Hummingbird (Eupetomena macroura; body mass 8.6 g), during overnight exposure to natural conditions of photoperiod and ambient temperatures. All three species entered torpor. In both A. versicolor and E. macroura, individuals entered torpor even if they had access to feeders up to the time of sunset. In contrast, M. fuscus was less prone to enter torpor and did so mainly if it had been fasting for more than two hours before sunset. Furthermore, M. fuscus often spent the whole night in torpor, whereas the two other species entered torpor for a variable, often short, period of the night. We observed more than one torpor bout during a single night in all three species. We suggest that multiple nocturnal torpors result from interruption of the normal torpor pattern by some (unknown) external stimuli. Any interrupted torpor was always followed by a new entry into torpor, supporting the view that there is a body mass threshold below which the hummingbirds must enter torpor Our data also indicate that these hummingbird species might use torpor even if they are not energetically stressed.

RESPONSE TO TEMPERATURE IN THE OXYGEN-UPTAKE OF AWAKE AND DORMANT FROGS (AMPHIBIA, LEPTODACTYLIDAE)

In southeastern Brazil the leptodactylid frogs Leptodactylus fuscus and Physalaemus fuscomaculatus enter dormancy during the dry season. Oxygen uptake was measured in awake and dormant groups of both species in a temperature range at which these frogs are usually exposed throughout the year. Oxygen uptake was lower for dormant groups at high temperature, and a lack of response to temperature was reported between 20 - 25 C in the dormant group of both species. This temperature-intensitive range can be considered an adaptive feature to save fat reserves during dormancy.