Stomach contents of Latimeria chalumnae and further notes on its feeding habits

Synopsis Stomach contents of three Latimeria chalumnae dissected in Japan support the hypothesis that the coelacanth is a predominantly nocturnal bottom or near-bottom drift feeder. Prey items identified in this study (Ilyophis brunneus, Cephaloscyllium sufflans and Beryx decadactylus) and those reported previously are mostly benthic or epibenthic dwellers. The drifting of the coelacanth in a headstanding posture would account for the easy capture of prey that moves within or just above the bottom strata at night.     

Open-Air Litter Foraging in the Nasute Termite Longipeditermes longipes (Isoptera: Termitidae)

The Southeast Asian nasute termite Longipeditermes longipes forages on the open ground on leaf litter. Its monomorphic workers carry back food balls in their mandibles while dimorphic soldiers defensively surround the marching columns and the foraging patches. When mechanically disturbed, workers hide under the litter, whereas antennating soldiers face as closely as possible the source of disturbance. Foragers prefer the lower, nitrogen-rich layer of the litter. Soldier behavior and column organization (returning workers in the center lanes, outgoing workers in the two flanking lanes) are similar to those in the related genera Hospitalitermes and Lacessititermes, which, however, tend to forage above ground.     

Summer drought alters plant-mediated competition between foliar- and root-feeding insects

Summer droughts are predicted to increase in severity and frequency in the United Kingdom, due to climate change. Few studies have addressed the impacts of drought on interactions between species, and the majority have focussed on increases in CO₂ concentration and changes in temperature. Here, the effect of experimental summer drought on the strength of the plant‐mediated interaction between leaf‐mining Stephensia brunnichella larvae and root‐chewing Agriotes larvae was investigated. Agriotes larvae reduced the abundance and performance of S. brunnichella feeding on a mutual host plant, Clinopodium vulgare, as well as the rate of parasitism of the leaf‐miner. The interaction did not, however, occur on plants subjected to a severe drought treatment, which were reduced in size. Changes to summer rainfall, due to climate change, may therefore reduce the occurrence of plant‐mediated interactions between insect herbivores.     

Efficacy of a remote-controlled, positive-reinforcement, dog-training system for modifying problem behaviors exhibited when people arrive at the door

This study was conducted to determine the efficacy of a multi-step, positive-reinforcement training protocol, involving a remote-controlled food reward dispenser, for treatment of excessive barking, jumping, and crowding of the door by dogs when people come to the door. In Experiment 1, we tested the multi-step protocol in a laboratory setting to determine whether the protocol is successful in a controlled environment when implemented by dog trainers. Six dogs with a history of problem behaviors at the door were trained to run to a platform with a rug on it, lie down and stay (“down-stay”) for 1 min while common household door distractions such as loud knocking, ringing doorbells, and running people were presented. The dog's ability to remain in a down-stay for 1 min with such distractions was measured before and after training. During training, the number of training trials required and the numbers of trials performed correctly and incorrectly were recorded for each dog. The results revealed that dogs remained in a down-stay with distractions significantly longer after training (60 ± 0.0 s) than before (5 ± 1.18 s) (P = 0.016). Dogs completed the training protocol in 8 d with only 8.4% incorrect trials, and in a similar number of trials with a coefficient of variation of 10.6%. These results indicated that this protocol was a good candidate for testing in a clinical setting, a home situation with owners doing the training. In Experiment 2, 15 dogs were trained by their owners to run to a rug or bed, lie down, and stay for 1 min while their owners answered the door. After training, barking decreased from 19.3 ± 4.62 barks/min to 2.1 ± 0.79 barks/min (P < 0.0001), jumping decreased from 8.2 ± 2.12 jumps/min to 0.02 ± 0.02 jumps/min (P < 0.0005) and time spent within 0.3 m of the door when visitors were outside decreased from 84.5% ± 4.23% to 0.0% ± 0.00% (P < 0.0001). Percent time spent in contact with the visitor when the visitor was inside decreased from 69.2% ± 4.19% to 0.18% ± 0.13% (P < 0.0001). Additionally, owner perception of their dog's behavior improved significantly (P < 0.0001). Six dogs that were not trained with the protocol showed no significant improvement (P = 0.344).     

Cephalopod dietary specialization and ontogenetic partitioning of the Australian weasel shark Hemigaleus australiensis White, Last & Compagno

The diet and ontogenetic partitioning of the Australian weasel shark Hemigaleus australiensis was examined in Moreton Bay, south-east Queensland, Australia. The index of relative importance ( I _RI) revealed a highly specialized diet, consisting entirely of cephalopod molluscs (99·6% I _RI) and crustaceans (0·4% I _RI). Benthic octopus (Octopoda) dominated the diet, accounting for 96·7% I _RI. A highly significant difference was found between the stomach contents of juvenile and sub-adult and adult Australian weasel sharks. Dietary specialization increased with ontogeny and fish ≥1000 mm in total length ( L _T) fed almost exclusively on octopus (98% I _RI). A highly significant difference was found between the L _T of Australian weasel sharks from coral and sand and seagrass sites. At the coral site 75·4% of fish were mature while at the sand and seagrass site only 16·1% were mature. This spatial segregation may be attributed to shifting energy requirements associated with ontogeny and the relative abundance of large octopus at the coral site. Hemigaleus australiensis resides in an area of high shark diversity and its specialized cephalopod diet may reduce competition for food with other Carcharhiniformes whose prey comprises predominantly teleosts.     

贵州烂泥沟金矿区苔藓植物及其生态修复潜力分析

对世界级的大型卡林型金矿一贵州贞丰烂泥沟金矿区的苔藓植物进行初步调查。258份标本经鉴定共有15科37属81种。丛藓科（Pottiaceae）、真藓科（Bryaceae）、牛毛藓科（Ditrichaceae）和珠藓科（Bartramiaceae）植物适于在该区生长。对金灰藓（Pylaisiella polyantha）、黄色真藓原变种（Bryum pallescens var．pdlescens）、牛毛藓（Ditrichum heteromallum）、阔叶小石藓（Weisia planifolia）、短叶小石藓（Weisia semipatlida）、红毛细羽藓（Cyrio-hypnum versicolor）6种植物及其基质中的9种重金属元素进行测定,基质中As的含量达到222．378mg kg^-1,为国家3级标准（40mg kg^-1）的5．56倍;Hg的含量达23．516mg kg^-1,为国家3级标准（1．5mg kg^-1）的15．68倍,污染状况比较严重。通过对富集系数的分析来看,每种苔藓植物对至少3种以上的复合重金属有一定的富集能力,可以作为复合重金属含量较高矿山的生态修复与重建的先锋植物。     

Establishment of a long-term culture system for rat colon epithelial cells

Summary The aim of this study was to establish a long-term culture system for rat colon epithelial cells. Colonic crypts were isolated by incubating a 4-cm-long rat colon segment cut longitudinally with an ethylenediaminetetraacetic acid [disodium salts]-containing buffer, taken up in conditioned medium from the normal rat kidney fibroblast cell line NRK (i.e., the supernatant of pure NRK cultures), directly plated on mitomycin C-treated NRK cells and subcultured with conditioned medium from NRK cells. Cells started to migrate out of the crypts shortly after plating them on NRK feeder layers. Some of the crypts fell apart during the isolation procedure, whereas the vast majority of them did it within 1 to 2 h after plating. The cells proliferated extremely slowly but continuously over a period of 4 mo and were epithelial because they expressed cytokeratin 19 and were stained by crystal violet at pH 2.8. In conclusion, the experimental system described in this study allows to maintain rat colon epithelial cells for up to 4 mo in culture and can be used to study the effects of a variety of tumor-modulating factors on growth and gene expression of normal colon epithelial cells in vitro.     

Performance of ad libitum fed dairy calves weaned using fixed and individual methods

The increasing availability of automated milk dispensers on dairy farms facilitates ad libitum milk supply but weaning calves from high milk allowances is challenging. This study evaluated effects of gradual weaning methods on starter intake, growth, selected blood parameters and weaning distress in ad libitum fed dairy calves during weaning and early post-weaning periods. Thirty-six male Holstein (n = 30) or crossbred (n = 6) calves were individually housed from days 2 to 14 of age and had ad libitum access to milk replacer (MR) from teat buckets. From days 15 to 84 of age, calves were grouped and had ad libitum access to MR, starter, straw and water from automated feeders. At day 35, calves were blocked (age and breed), and randomly assigned to a weaning method: (1) linear fixed (LIN), MR supply was stepped down to 6 l/day on day 36, and linearly reduced between days 36 to 63 from 6 to 2 l/day. (2) Step-down (STEP), MR supply was stepped down to 6 l/day from days 36 to 48, 4 l/day from days 49 to 56 and 2 l/day from days 57 to 63. (3) Dynamic (DYN), at day 36, MR supply was reduced for each individual calf to 75% of the average voluntary consumption between day 29 and 35, then maintained for 9 days, reduced to 50% for 10 days, and to 25% for 9 days. The DYN calves received more MR during weaning than LIN calves, whereas STEP calves had intermediate MR intake. Starter intake was not affected by weaning method. The DYN calves (1.33±0.08 kg/day) grew faster and were heavier than STEP calves (1.10±0.08 kg/day) during post-weaning period, whereas no difference was observed between LIN calves (1.23±0.08 kg/day) and others. At days 70 and 84, concentrations of β-hydroxybutyric acid were higher in LIN calves compared to STEP and DYN calves. Hair cortisol concentrations were not affected by weaning method. During the gradual weaning process CP intake seemed to recovered earlier than metabolizable energy (ME) intake in all treatments, suggesting that ME rather than CP could be the first limiting factor for growth during weaning. These results highlight the post-weaning benefits of DYN and LIN weaning methods when compared with more abrupt step-down strategies.