Normal nasal cavity and paranasal sinuses in brown lemurs Eulemur fulvus: computed tomography and cross-sectional anatomy

Background Far less is known about the normal anatomy of the nasal cavity of Eulemur fulvus; no computed tomography (CT) scan has ever been published. Methods Relevant CT scans were taken in the transverse, dorsal and longitudinal planes. These scans were compared with anatomical sections of heads. Results Computed tomography scans revealed almost all nasal structures, but cannot differentiate between the various layers of the nasal mucosa. Results show a double‐scroll arrangement of the ventral nasal concha. The dorsal nasal concha protrudes into the maxillary sinus, but no protrusion into the frontal sinus was observed. The ethmoturbinate I is completely closed back on itself and rostrally voluminous. Conclusions This work shows that at a clinical level, the integrity of the different turbinates can easily be appreciated from a simple CT scan. It will assist clinicians to evaluate pathological conditions that affect the nasal region.     

Biological control by two exotic parasitoids: eight-year population dynamics and life tables of the arrowhead scale

To determine the process of regulation of Unaspis yanonensis (Kuwana) (Hemiptera: Diaspididae) by the two introduced parasitoids, Aphytis yanonensis DeBach et Rosen and Coccobius fulvus (Compere et Annecke) (Hymenoptera: Aphelinidae), the temporal changes in the population density of U. yanonensis as well as the parasitism rates were monitored for eight years before and after the release of the two parasitoids in a Satsuma mandarin orange (Citrus unshiu Marc. (Rutaceae)) orchard. From 2–4 years after the release, the parasitism rate by C. fulvus gradually increased, eventually reaching 70%, while that by A. yanonensis showed a weak increase, remaining under 12%. During this period, the host density decreased to about 1/100 of the initial density. After the drastic decrease, the host density remained under 1/60 of the level previous to the release for at least 2 years with the populations of both parasitoids persisting. To estimate the ability of the two parasitoids to regulate the populations of U. yanonensis, life tables of U. yanonensis under natural conditions and predator/parasitoid-exclusion (bagged) conditions were compared. It was demonstrated that C. fulvus and A. yanonensis impose about 70% mortality rate on the host at mature adult stages and about 30% on the host at immature adult stages. The results have strongly confirmed the high capability of the two parasitoids as biological control agents for U. yanonensis, which was suggested by earlier studies. However, contrary to those studies, the present study did not support the complementarity of the two parasitoids in regulating the host population, suggesting that the effectiveness of C. fulvus alone in regulating the host population at low levels.     

Rapid change in the settling behavior of the arrowhead scale Unaspis yanonensis as an avoidance mechanism against introduced parasitoids, Aphytis yanonensis and Coccobius fulvus

Abstract Parasitoids are thought to exert immense selection pressures that shape the traits of herbivores. We examined whether two species of parasitoid wasps, Aphytis yanonensis DeBach et Rosen and Coccobius fulvus Compere et Annecke (Hymenoptera: Aphelinidae), affect the settling behavior of the arrowhead scale Unaspis yanonensis Kuwana (Hemiptera: Diaspididae), in order to demonstrate the evolution of antiparasitism behavior of herbivores using parasitoids in the field. We used the following five methods: a comparison of parasitism risk in different settling behaviors‐parasitoid introduction into a parasitoid‐free population; a comparison of the settling behavior between parasitoid‐present and parasitoid‐free populations; a common garden experiment, in which scales were transferred from parasitoid‐present and parasitoid‐free populations into the same garden; and a laboratory observation of the settling behavior of the first instars derived from the two population categories. Both parasitoids were introduced into a parasitoid‐free population in Wakayama in 1987, and the settling mode of the scales was examined in 1987, 1994, and 1995. The introduction of parasitoids modified the scale‐settling mode so that more crawlers settled under another scale (called burrowing), which was consistent with the results observed in parasitoid‐present (including South China) and parasitoid‐free populations. Moreover, only the burrowing scale exhibited a lower parasitism rate compared to scales settling singly and being burrowed. The common garden experiment demonstrated that scales introduced from the parasitoid‐present population had a greater proportion of burrowers than the parasitoid‐free population, even in the same field cage under parasitoid‐free conditions. Laboratory observations demonstrated that the population difference in parasitism rate was principally due to intrinsic differences in the settling behavior of nymphs; some first‐instar nymphs derived from the parasitoid‐present population burrowed under another scale settled. These results strongly suggest that the natural selection pressure imposed by the parasitoids modified the settling behavior of the arrowhead scale.     

Fitness cost of parasitoid avoidance behavior in the arrowhead scale, Unaspis yanonensis Kuwana

We examined trade-offs between fitness components and the parasitoid avoidance behavior of the arrowhead scale, Unaspis yanonensis Kuwana (Homoptera: Diaspididae). We examined the performance of two settling modes: singleton and double settling with the burrower under the burrowee. Each of these modes differs in vulnerability to parasitism by Aphytis yanonensis DeBach et Rosen and Coccobius fulvus Compere et Annecke (Hymenoptera: Aphelinidae), and performance. Field and laboratory observations revealed smaller body size and lower parasitism of burrower scales, while both singletons and burrowees showed the opposite tendency (larger body size and a greater parasitism rate). Laboratory observations under parasitoid-free conditions revealed greater mortality and reduced growth rate for simulated burrowers than for singletons during the 40-day nymphal period. This suggests that competition for food resources reduces performance. The results also suggest trade-offs between parasitoid avoidance and resource acquisition ability in U. yanonensis. The trade-offs also explain our previous findings, that introduction of the parasitoids increased the proportion of burrowers, but that within seven years equilibrium was reached at fairly low levels (ca. 5%) in the field, even under intense parasitism.     

Genetic assessment of a white-collared x red-fronted lemur hybrid zone at Andringitra,Madagascar

We examined a purported lemur (Eulemur fulvus rufusxE. albocollaris) hybrid zone at Andringitra, Madagascar, using sequences from five genes (one mitochondrial gene (d-loop) and four nuclear introns (hemopexin, malic enzyme, ceruloplasmin, and microsatellite 26 flanking region)), from 60 individuals (E. albocollaris (n = 16), E.f. rufus (n = 14), E. collaris (n = 9), and purported hybrids from Andringitra (n = 21)). Diagnostic (d-loop and microsatellite 26) and private sites (all other genes) were found in all gene regions for E. albocollaris and E.f. rufus. Also, private sites were found for the purported hybrid population in two gene regions (d-loop and ceruloplasmin). When the putative hybrids were examined for diagnostic and private markers, 18 of 21 were found to contain markers from both E. albocollaris and E.f. rufus populations. The remaining three individuals were found to contain only markers for E. albocollaris. These results indicate that the population at Andringitra is a hybrid population between E. albocollaris and E.f. rufus.     

Thermal biology of the fossorial rodent Ctenomys fulvus from the Atacama desert, northern Chile

The Andean tuco-tuco, Ctenomys fulvus (Rodentia: Ctenomyidae) inhabits one of the most arid regions of the world, the Salar de Atacama, Northeast of Antofagasta, Chile (23°17′06″S, 68°05′43″W; 2.240 m.a.s.l). We found that a stable microclimate in burrows, a low evaporative water loss (EWL), and a diet of roots (59% water content) are the main factors that permit the survival of this fossorial species in harsh desert conditions. Large circadian variation in T_a was observed above ground. Daily ΔT_a (T_a max − T_a min) = 37.9±0.2°C in summer and in winter. In contrast, circadian variation of T_a inside the burrows was only 5.8±0.5°C in the same seasons. Relative humidity (RH) was 1.9–3.1% during the day, increasing to maximum values of 27% at night and early morning. Inside the burrows RH was higher and quite stable, ranging between 53.1 and 65%, independent of the time of day and season. EWL, measured between 10 and 25°C, was low (1.26 mg/g h), and a moderate increase of 13–20% was observed at higher temperatures. The low EWL may prevent dehydration. However, because of the low heat loss capability, animals became hyperthermic (0.8–1.6°C) in dry air at T_a=30–35°C. As T_a during afternoon normally exceeded 35°C, the microclimate of burrows provided the only way to avoid the lethal effects of hyperthermia.     

The geography of diversification in the mormoopids (Chiroptera: Mormoopidae)

The traditional explanation of the distribution of the Mormoopidae is that this family originated in southern Central America or northern South America, later expanding its range north to Mexico and the West Indies, and differentiating into eight species. An alternative fossil-based hypothesis argues that the family originated in the northern Neotropics, reached the Caribbean early in its history, and dispersed to South America after the completion of the Isthmus of Panama. The present study analyses new and previously published sequence data from the mitochondrial 12S, tRNA^val, 16S, and cytochrome b , and the nuclear Rag 2, to evaluate species boundaries and infer relationships among extant taxa. Fixed differences in cytochrome b often coincide with published morphological characters and show that the family contains at least 13 species. Two additional, morphologically indistinct, lineages are restricted to Suriname and French Guiana. Phylogeny-based inferences of ancestral area are equivocal on the geographical origin of mormoopids, in part because several internal nodes are not resolved with the available data. Divergences between Middle American and Antillean populations are greater than those between Mexico/Central America and South America. This suggests that mormoopids diversified in northern Neotropics before entering South America. A northern neotropical origin for mormoopids is congruent with both the Tertiary fossil record and recent phylogenetic hypotheses for the sister family to the Mormoopidae, the Phyllostomidae.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 101–118.     

Feeding enrichment by self‐operated food boxes for white‐fronted lemurs (Eulemur fulvus albifrons) in the Masoala exhibit of the Zurich Zoo

In the new Masoala exhibit of the Zurich Zoo four self‐operated food boxes were installed to encourage arboreal behavior and higher activity levels, and to increase the attractiveness to visitors of a group of three white‐fronted lemurs (Eulemur fulvus albifrons) and one Alaotran gentle lemur (Hapalemur griseus alaotrensis). Data obtained by direct observations with and without food boxes present were compared. In addition, visitors were surveyed to investigate attractiveness of the lemurs. Overall activity and locomotor behavior increased due to food box presentation. Furthermore, the visitor survey documented that the lemurs were spotted more often in trees when the food boxes were present. Because behavior patterns of the subjects approached natural levels with food boxes, the presentation of self‐operated food boxes seems a valuable tool to improve the captive environment of lemurs. Zoo Biol 0:1–10, 2005. © 2005 Wiley‐Liss, Inc.     

Correlates between locomotor anatomy and behavior in two sympatric of Lemur.

Sympatric populations of Lemur catta and Lemur fulvus show major differences in their occupation of canopy forest levels. Lemur catta is usually found in the lowest levels of the forest, and uses the ground for travel over 65% of the time. Lemur fulvus uses the upper levels of the canopy forest and is observed on the ground in less than 2% of all observations. Comparison of hindlimb musculoskeletal anatomy show statistically significant differences in the lengths of the long bones and the height of the talus. Differences also occur in ranges of tibio-talar and mid-talar joint mobility. The details of insertion of the biceps femoris muscle are distinct in the two species as is the relative mass of muscle associated with flexion of the pedal digits, and flexion of th tibio-talar joint. The metric and morphological differences in the hindlimb anatomy of Lemur catta and Lemur fulvus are consistent with differences in habitat and substrate utilization.     

A test of temporal and spatial density dependence in the parasitism rates of introduced parasitoids on host, the arrowhead scale (Unaspis yanonensis) in stable host–parasitoids system

Abstract: In 1980, two species of parasitoid wasps (Aphytis yanonensis DeBach et Rosen and Coccobius fulvus Compere et Annecke) were introduced to Japan from China as biological control agents to combat the arrowhead scale (Unaspis yanonensis Kuwana). These introductions represent one of the most successful projects in the history of biological control in Japan. To examine whether density dependent parasitism was inevitable for success of biological control, we tried to detect temporal and spatial density dependence in parasitism rates using time‐series data of scale density, as well as parasitism, over a 16‐year period. The work was conducted in a Satsuma mandarin orange (Citrus unshiu Marc.) orchard in which we previously demonstrated that the system appeared to have stabilized after a decline in scale density following the introduction of the parasitoids. Earlier work also indicated that C. fulvus contributes most to the reduction in, and the stability of, scale density. In this study, we examined: (1) the relationship, on a whole‐orchard basis, between scale density and the rates of parasitism by A. yanonensis, C. fulvus, and a combination of the two species; (2) whether parasitism was positively correlated to scale density on a single‐tree basis among generations and (3) whether spatial density dependence was detectable within generations on an individual‐tree basis. Parasitism by A. yanonensis was temporally density‐dependent on scale population density at the whole‐orchard level, while parasitism by C. fulvus was not. Parasitism by A. yanonensis or by C. fulvus was rarely positively correlated to scale density at the single‐tree level, and spatial density‐dependence was hardly detected at all at this level. Most analyses of combined parasitism rates were similar to rates of parasitism by C. fulvus alone. Contrary to conventional wisdom of biological control theory, this study demonstrates that density dependence is not necessarily detected, even in a system in which a natural enemy has long held pest density stable at low levels.