Digesta retention time and recovery rates of ants and termites in Chinese pangolins (Manis pentadactyla).

Pangolins are myrmecophagous mammals whose biology and ecology remain poorly studied. Termite mandibles and ant head capsules are the two primary remains found in pangolin feces. Determining the retention time of insect cuticles is important for understanding the digestive physiology of pangolins, while determining the recovery rate of termites and ants in feces is required to estimate the number of these prey items that are consumed by pangolins. In this study, the authors conducted feeding trials with captive Chinese pangolins (Manis pentadactyla). Sixty grams of the fungus-growing termite Odontotermes formosanus (18,816 individuals) and 15-20 g of the yellow crazy ant Anoplolepis gracilipes (14,400-19,200 individuals) were fed to each pangolin. After feeding, pangolin feces were collected daily for 1 week. The authors also assessed the accuracy of using chromium (III) oxide powder (Cr2 O3 ) as a proxy for determining gut passage time, as has been done in previous studies. The results showed that remaining termite mandibles and ant head capsules in feces peaked at 66 and 90 hr after feeding and their recovery rates were 0.35 ± 0.10 and 0.65 ± 0.04, respectively. In both feeding trials, the retention time of Cr2 O3 was much shorter than that of the termite mandibles and ant head capsules, indicating that Cr2 O3 is not an appropriate indicator for estimating food retention time of myrmecophagous animals. Our results revealed that the ant head capsules were preserved better in feces compared with the termite mandibles, suggesting that termites may be considerably underestimated in the feces of wild pangolins.

Putative source and niche shift pattern of a new alien ant species (Odontomachus troglodytes) in Taiwan.

Alien species may pose substantial impacts on biodiversity around the globe through international trade and travel. A niche shift hypothesis was proposed to explain the adaptive change of alien or invasive species in new habitats. However, whether niche shifts occur in alien species likely depends on both characteristics inherent to the species itself and its original distribution. Here we identified a newly exotic trap-jaw ant (Odontomachus troglodytes) in Taiwan by morphological and phylogenetic analyses. The possible distribution range and the niche shift pattern were evaluated using ecological niche modelling. The results indicated that exotic O. troglodytes in the newly distributed area displayed a significant niche shift with low niche overlap and high niche expansion. This study reveals a long-distance invasive event from central Africa to Southeast Asia (more than 10,000 km) and predicts the potential distribution range of this new alien species in Taiwan.

Diet composition of an escaped captive-born southern tamandua (Tamandua tetradactyla) in a nonnative habitat in Asia.

Studies on the role of natural predatory instincts in captive-born mammalian myrmecophagy are rare. Consequently, researchers rely extensively on case reports to learn more about the contexts in which predatory behavior occurs among such animals. In this study, we recorded an uncommon case of a captive-born southern tamandua (Tamandua tetradactyla) that accidentally escaped from a zoo into a nonnative habitat in Asia. The southern tamandua was found alive 3 months later. Two fresh fecal samples were obtained, and the diet composition was examined. Three termite species (one family, three genera), and 14 ant species (four subfamilies, nine genera) were identified in the fecal samples. The studied southern tamandua preyed on terrestrial and arboreal ants and termites, as the wild populations of its species do. Ants of the subfamily Myrmicinae and termites of the subfamily Nasutitermitinae were the most abundant prey items in the samples, which is consistent with related reports on the wild populations. Soldier ants constituted <1% of the prey items in the fecal samples, suggesting that the southern tamandua likely avoided preying on ants of the soldier caste. Fungus-growing termites Odontotermes (Isoptera: Macrotermitinae), which are not native to neotropical regions, were also ingested by the southern tamandua. This study provides information on how a captive-born mammalian myrmecophagy applies its natural feeding instincts in nonnative natural settings.

Morphology of the Novel Basimandibular Gland in the Ant Genus Strumigenys (Hymenoptera, Formicidae).

In 1999, Barry Bolton postulated the presence of a basimandibular gland in the mandibles in all species of the ant genus Strumigenys, solely based on scanning microscopy observations. We now confirm the presence of this putative gland in the proximal outer part of the mandibles of 22 investigated species by histological and ultrastructural examination, including 10 short- and 12 long-mandibulate species. All species have a basimandibular gland, that is formed by 15-25 µm thick epithelial cells and belongs to class-1 following the standard classification of insect exocrine glands. We consider it a novel gland because of its peculiar bowl-shape and special arrangement of the microvilli that are confined to large vacuolar spaces instead of reaching the cuticle. The gland is most pronounced in S. mutica, particularly in the queen. In addition to this gland, we also found scattered class-3 intramandibular gland cells in the mandibles. Queens of S. mutica are peculiar in having a cluster of these cells in the distal tip of their mandibles. As this species is a social parasite, further research is required to determine whether the development of these mandibular glands is related to its parasitic lifestyle.

A 12-week rescue therapy by PrOD-based regimen for advanced fibrotic genotype-1 CHC patients who failed to pegylated interferon plus ribavirin.

BACKGROUND: Treatment of chronic hepatitis C (CHC) evolved rapidly due to the invention of interferon-free direct antiviral agents. Previous clinical trials showed combination therapy with paritaprevir/ritonavir, ombitasvir, and dasabuvir (PrOD) with or without ribavirin (RBV) can cure over 95% of genotype 1 CHC patients, regardless with cirrhosis or not. However, real-world data regarding the efficacy and safety of PrOD-based therapy in Asian HCV genotype 1 CHC patients are limited, especially for advanced-fibrotic patients who failed previous therapy with pegylated interferon (PEG-IFN) plus RBV. METHODS: Between January and October 2017, 60 advanced fibrotic (≥F3) genotype 1 CHC patients who failed previous therapy with PEG-IFN and received PrOD-based therapy for 12 weeks were retrospectively enrolled. Weight-based RBV 800 to 1200 mg/d was added for genotype 1b patients with cirrhosis and all genotype 1a patients. Sustained virological response (SVR) was defined by undetectable HCV RNA at the end and 12 weeks after the completion of therapy. RESULTS: The mean age was 63.2 ± 9.3 years, 26 (43.3%) of them were males and 20 (33.3%) were diagnosed to have liver cirrhosis. The mean baseline HCV RNA level was 6.19 ± 0.88 log10 IU/mL and 86.7% (52/60) of patients were infected by HCV genotype 1b. After PrOD-based therapy, the rates undetectable HCV RNA (<15 IU/mL) at week 2, 4, and 12 were 61.7%, 90.0%, and 100%, respectively; 69.6% (16/23) of patients with detectable HCV RNA at week 2 were < 100 IU/mL. Pruritus, fatigue, headache, insomnia, and dizziness were the most common patient-reported adverse events. Grade 2 hyperbilirubinemia were found in 21.6% (13/60) of patients during study period and all belonged to unconjugated hyperbilirubinemia. After posttherapy follow up, all 60 patients (100%) achieved SVR. CONCLUSION: Our real-world data in Taiwan revealed that PrOD-based rescue therapy is well-tolerated and highly effective for genotype 1 CHC patients with advanced fibrosis failing previous therapy with PEG-IFN plus RBV.