Possible Batesian mimicry to sexually different models in the tussock moth Numenes albofascia with a great sexual color dimorphism

Mimicry with warning colors includes Batesian and Müllerian mimicries. If we divide mimicry by sex, there are theoretically four types of mimicry: unimodal, female-limited, male-limited and dual mimicry. The latter three cases cause sexual dimorphism in body color and marking pattern but are rarely reported. In this study, we show that the tussock moth Numenes albofascia is possibly a dual mimic. The wing color and marking pattern of male and female N. albofascia are completely different, with the male's pattern resembling that of the smoky moth Pidorus atratus, while the female pattern resembles that of the tiger moth Arctia caja. Body size also differs greatly between the sexes of N. albofascia, matching the mimicry model species of each sex. These moths are distributed sympatrically in Japan, and their adult seasons overlap with each other. According to lizard feeding experiments, N. albofascia is palatable, while both male and female model species are unpalatable. Actograms in the laboratory and the light trapping in the field suggest that females of N. albofascia fly actively from sunset to midnight, while males fly during the twilight period around dawn. Therefore, male and female N. albofascia might be Batesian mimics of diurnally active P. atratus and nocturnally active A. caja, respectively, and the great sexual dimorphism of this moth could be caused by dual mimicry.     

Palatability in sheep and in vitro nutritional value of dried and ensiled sainfoin (Onobrychis viciifolia) birdsfoot trefoil (Lotus corniculatus), and chicory (Cichorium intybus)

Abstract

Three temperate forages, sainfoin, birdsfoot trefoil, and chicory, characterized by elevated contents of plant secondary compounds, were compared to a ryegrass-clover mixture (control) in dried (Experiment 1) and ensiled form (Experiment 2) in their palatability and nutritional value. Palatability was measured in adult wethers (n = 6) allowed to choose between the familiar control forage and one of the three test plants. Palatability index was calculated from differences in intake of control and test plants measured after given times. Generally at first contact, palatability of the unfamiliar plants was low. Lag time until palatability index approached or exceeded a value of 100 was 2 – 5 d, but could not be related to the content of condensed tannins. Sainfoin had a high palatability, the highest content of condensed tannins (77.4 ± 10.23 g/kg DM), a high content of duodenally utilisable crude protein (94.7 ± 16.87 g/100 g CP), and a high content of metabolizable energy (9.5 ± 0.38 MJ ME/kg DM), making this plant most promising for various purposes including anthelmintic action.     

Effects of large herbivores on wood pasture dynamics in a European wetland system

Whether self-regulating large herbivores play a key role in the development of wood-pasture landscapes remains a crucial unanswered question for both ecological theory and nature conservation. We describe and analyse how a ‘partly self-regulating’ population of cattle, horses and red deer affected the development of the woody vegetation in the Oostvaardersplassen nature reserve (Netherlands). Using aerial photographs from 1980 to 2011, we analysed the development of shrubs and trees. Before the large herbivores were introduced in the Oostvaardersplassen in 1983, the woody vegetation increased and vegetation type significantly affected the number of establishments. Cover of woody species increased further from 1983 to 1996, not only by canopy expansion but also by new establishments. After 1996, cover of the woody vegetation decreased from 30% to <1% in 2011 and no new establishments were seen on the photographs. Survival of Sambucus nigra and Salix spp. increased with increasing distance to grassland, which is the preferred foraging habitat of the herbivores. These results support the hypothesis of Associational Palatability. In addition, our results show that the relative decline in cover of S. nigra and Salix spp. over a certain period was negatively correlated with the cover of S. nigra in the beginning of this period, presenting some evidence for the Associational Resistance and Aggregational Resistance hypothesis. Our research shows aspects necessary for the woodland–grassland cycle, such as a strong decline of woody vegetation at high numbers of large herbivores and regeneration of shrubs and trees at low densities. Thorny shrubs, which are important for the cycle, have not yet established in the grasslands. It seems that a temporary decline in herbivore numbers is necessary to create a window of opportunity for the establishment of these woody species.     

Quality of three muscles from suckler bulls finished on concentrates and slaughtered at 16 months of age or slaughtered at 19 months of age from two production systems

There is a requirement in some beef markets to slaughter bulls at under 16 months of age. This requires high levels of concentrate feeding. Increasing the slaughter age of bulls to 19 months facilitates the inclusion of a grazing period, thereby decreasing the cost of production. Recent data indicate few quality differences in longissimus thoracis (LT) muscle from conventionally reared 16-month bulls and 19-month-old bulls that had a grazing period prior to finishing on concentrates. The aim of the present study was to expand this observation to additional commercially important muscles/cuts. The production systems selected were concentrates offered ad libitum and slaughter at under 16 months of age (16-C) or at 19 months of age (19-CC) to examine the effect of age per se, and the cheaper alternative for 19-month bulls described above (19-GC). The results indicate that muscles from 19-CC were more red, had more intramuscular fat and higher cook loss than those from 16-C. No differences in muscle objective texture or sensory texture and acceptability were found between treatments. The expected differences in composition and quality between the muscles were generally consistent across the production systems examined. Therefore, for the type of animal and range of ages investigated, the effect of the production system on LT quality was generally representative of the effect on the other muscles analysed. In addition, the data do not support the under 16- month age restriction, based on meat acceptability, in commercial suckler bull production.     

Rangeland degradation in Swaziland: Dip tank use effects on range condition and grazing capacity in three soil types

This study examined rangeland condition and degradation characteristics of the semi‐arid savannahs of Swaziland in response to distance from dip‐tank points in three soil types. Eight dip‐tanks, three each in sandy and loamy, and two in stony soils, were selected. Two transects (1 km) radiating from each dip‐tank were established. Total herbaceous yield (range: 176–363.8 kg DM ha^?1) and grazing capacity (47.5–111.5 ha LSU^?1) were very low throughout the studied areas. Palatability and ecological values of grasses were 18.7–67.6% and 43.2–64.1%, respectively. Most sites were dominated by woody seedlings and saplings (<0–2 m). Most vegetation variables did not respond considerably to distance, soil types and sites within soil types. When all measured variables were combined, the results showed a generally poor range condition scores across distance points from the dip‐tank. A holistic restoration programme with full involvement of communal farmers, experts, policy makers and extension workers is recommended.     

Prediction of beef eating quality in France using the Meat Standards Australia system

An experiment was set up for (i) comparing Australian and French consumer preferences to beef and to (ii) quantify how well the Meat Standards Australia (MSA) grading model could predict the eating quality of beef in France. Six muscles from 18 Australian and 18 French cattle were tested as paired samples. In France, steaks were grilled ‘medium’ or ‘rare’, whereas in Australia ‘medium’ cooking was used. In total, 360 French consumers took part in the ‘medium’ cooking test, with each eating half Australian beef and half French beef and 180 French consumers tested the ‘rare’ beef. Consumers scored steaks for tenderness (tn), juiciness (ju), flavour liking (fl) and overall liking (ov). They also assigned a quality rating to each sample: ‘unsatisfactory’, ‘satisfactory everyday quality’ (3*), ‘better than everyday quality’ (4*) or ‘premium quality’ (5*). The prediction of the final ratings (3*, 4*, 5*) by the French consumers using the MSA-weighted eating quality score (0.3 tn + 0.1 ju + 0.3 fl + 0.3 ov) was over 70%, which is at least similar to the Australian experience. The boundaries between ‘unsatisfactory’, 3*, 4* and 5* were found to be ca. 38, 61 and 80, respectively. The differences between extreme classes are therefore slightly more important in France than in Australia. On average, even though it does not have predictive equations for bull meat, the mean predicted scores calculated by the MSA model deviated from observed values by a maximum of 5 points on a 0 to 100 scale except for the Australian oyster blade and the French topside, rump and outside (deviating by <15). Overall, the data indicate that it would be possible to manage a grading system in France as there is high agreement and consistency across consumers. The ‘rare’ and ‘medium’ results are also very similar, indicating that a common set of weightings and cut-offs can be employed.     

Preference of intake of different tree leaves preserved with drying and ensiling by nyala antelope (Tragelaphus angasii)

It is recommended that browse should be an important part of diets for browsing and intermediate feeding type ruminants. However, provision of browse in winter time is problematic for many zoos located in the temperate climate. Drying or freezing of branches are commonly practiced solutions to this problem, but ensiling of tree leaves could also be an attractive option. The aim of this study was to determine the effect of drying and ensiling of different tree leaves on preference of their intake by nyala antelope (Tragelaphus angasii), an intermediate feeding type ruminant. A study was conducted on five nyala fed a standard diet (meadow hay, dehydrated chopped lucerne and limited concentrates) before and during the study. Preference of intake of five feeds was tested: dried maple (A. platanoides), oak (Q. robur), willow (S. alba), and ensiled maple and lime (T. cordata) leaves. Each day two tested feeds were offered to each animal. After 4 h of presentation, feed refusals were weighed and preference ratio for each tested feed and animal was calculated. Then, preferences were ranked using a pairwise comparison chart. Dried maple and oak leaves were preferred more than other leaves whereas ensiled lime leaves were the least preferred. On the other hand, ensiled and dried maple leaves were equally preferred. Results of this study showed that palatability of ensiled tree leaves should not be a concern when feeding nyala, and likely also other browsing or intermediate feeding type ruminants, but palatability of silage may depend on the species of tree.     

Leaf nutrient content and host plant selection by leaf-cutter ants, Atta laevigata, in a Neotropical savanna

The selection of nutrient-rich leaves by leaf-cutter ants ( Atta spp.) is thought to be of indirect benefit to these ants by promoting the growth of their symbiotic fungus. However, relatively few studies have analyzed the influence of leaf nutrient content on host plant selection by leaf-cutter ants, and conflicting results have been found. We compared the content of eight nutritional elements plus the non-nutrient aluminum between leaves harvested by colonies of Atta laevigata (Smith) (Hymenoptera: Formicidae: Attini) and leaves collected randomly within their foraging areas. In addition, we evaluated whether leaf nutrient content explained the frequency with which these ants attacked and defoliated some of the tree species found in the study area. For 2 years, we monitored 17–26 trees from 15 species and determined the number of times each plant was attacked and the amount and type of foliage removed. Leaves harvested by A. laevigata presented significantly higher concentrations of N, P, K, Zn, and Cu than those collected randomly. This result is likely to reflect the foraging pattern presented by these ants, which were selective both in terms of the plant species and age of leaves most commonly attacked. Young leaves were the only or the main leaf type exploited in many species, and in comparison to mature leaves these presented significantly higher concentrations of P and K. Large differences in the mean number of ant attacks on the tree species studied were also observed, and those presenting more leaf N tended to be the most frequently attacked.     

Seasonal variation in secondary plant compounds in relation to the palatability of Pteridium aquilinum

A correlation was found between the levels of cyanide production and of tannins and the palatability of bracken Pteridium aquilinum L. Kuhn to sheep and deer and to the phytophagous locust Schistocerca gregaria. In the case of the mammals, cyanogenesis, which is genetically polymorphic, appeared to be a complete deterrent to feeding, but tannins probably also play a part. For the insect there were two times during the season when feeding was strongly inhibited and these corresponded to peaks in cyanogenesis in the young developing fronds late May/early June and in tannins which reached the highest level in late August/early September. Changes in total flavonoid levels did not appear to correlate with such feeding preferences.     

The acceptability of mosses as food for generalist herbivores, slugs in the Arionidae

Observations in the held suggest that moss shoots are seldom freely consumed by either vertebrate or invertebrate herbivores, but damage to immature capsules by slugs is abundant. Palatability of the mosses Mnium hornum, Brachythecium rutabulum and Funaria hygrometrica to the generalist herbivores, Arion subfuscus and A. rufus was investigated by offering the slugs four stages in the moss life cycle; protonema, leafy shoot, immature capsule and mature capsule. The slugs showed a preference for immature capsules and protonemata in all moss species tested. Consumption of shoots of M. hornum and B. rutabulum was negligible even after seven days starvation, but some shoots of F. hygrometrica were eaten in every overnight trial performed. Shoot extracts on starch-wafer substrate appeared to be more acceptable than intact shoots suggesting that the cell wall provides the barrier to free consumption. The form and location of a possible feeding deterrent is discussed.