Effects of six sugars on the longevity,fecundity and nutrient reserves of Microplitis mediator

Parasitoid adults can directly feed on floral nectar and honeydew containing monosaccharides and disaccharides. Oligosaccharides such as maltose, melezitose and raffinose are also found in honeydew but are rare in floral nectar. The effects of six different sugar resources on the longevity, fecundity and nutrient reserves of Microplitis mediator, a larval endoparasitoid in the cotton bollworm Helicoverpa armigera (Hübner) were determined in our laboratory. The results showed that both food and sex affected longevity of this wasp. Females and males of M. mediator fed with 1 M sucrose solution survived longer than controls fed with water (5.7- and 3.7-fold longer, respectively). When provided with sucrose, glucose or fructose solutions, the parasitoid generated 3.6- to 3.7-fold more offspring than controls, and 60–75% of these progenies were produced during the first 5 days. When separately given fructose, sucrose or glucose, this wasp accumulated fructose and total sugar at the highest level, which means a high sugar levels might lead to prolonging longevity and more offspring in M. mediator. In addition, compared with organisms fed galactose or raffinose, M. mediator fed sucrose or fructose accumulated high glycogen levels. Furthermore, in M. mediator, the lipid content declined with the advancing age. Females showed the slowest lipid metabolic rates when fed with sucrose, glucose, fructose, mannose and galactose solutions versus when fed with raffinose and control. In addition, only sucrose had a significant effect on lipid levels in males nearing the end of life.     

Changes in spatial and temporal distributions of Monochamus beetles along the fire severity in burned Pinus densiflora forests

Wildfire is an important disturbance factor in forest ecosystem and could affect the distribution of insects. Because Monochamus beetles are known vector insects of pine wood nematodes in Korea and burnt pine trees can be used as oviposition habitats for Monochamus beetles, we investigated changes in the spatial (among fire severity classes) and temporal (between years) distributions of M. alternatus and M. saltuarius. From late May 2017 to early October 2018, four multi-funnel traps with pheromone lure were installed in each fire severity class (unburned, light, light-moderate edge, moderate-severe edge, and severe). All traps were replaced fortnightly from May to October for two years. The spatial distribution of the two Monochamus beetles was significantly affected by fire severity. In particular, M. alternatus showed higher catches in the severely burned sites and responded positively to the fire. A similar number of M. saltuarius individuals were observed between 2017 and 2018, while more M. alternatus were caught in 2018 compared to 2017. Consequently, it was confirmed that the dead wood of P. densiflora caused by the wildfire had a great influence on the density of insects, especially M. alternatus.     

Cold storage of the egg parasitoids Trissolcus basalis (Wollaston) and Telenomus podisi Ashmead (Hymenoptera: Scelionidae)

Adults of Trissolcus basalis and Telenomus podisi were stored either at 15 or 18 °C after their immature development had been completed at 18 or 25 °C. Longevity of the parasitoids in the storage temperatures was evaluated, as well as fecundity and longevity following their return to 25 °C after different periods in reproductive diapause. Temperature during immature development influenced female longevity and highest mean longevity was obtained for females that developed to the adult stage at 25 °C and then were stored at 15 °C (ca. 13 months for T. basalis and 10 months for Te. podisi). For adults of T. basalis that developed at 25 °C, storage periods of 120 or 180 days at 15 or 18 °C did not affect fecundity. The fecundity of T. basalis females that developed at 18 °C and were stored for 120 days at 15 or 18 °C was not affected; however, after remaining for 180 days, fecundity was reduced in ca. 30 and 50%, respectively. Storage of Te. podisi adults at 15 or 18 °C significantly reduced fecundity. It is concluded that adults of T. basalis can be stored in the adult stage at 15 or 18 °C between two soybean crop seasons for mass production purposes, aiming the biological control of stink bugs.     

Sugar concentration and timing of feeding affect feeding characteristics and survival of a parasitic wasp

The availability of food sources is important for parasitoid survival, especially for those that inhabit ecosystems where nectar and honeydew are spatially or temporally scarce. Therefore, the value of even a single meal can be crucial for survival. Psyttalia lounsburyi is a parasitoid, and biological control agent, of the olive fruit fly, Bactrocera oleae. In order to improve our understanding of the basic nutritional ecology of P. lounsburyi and its role in survival we evaluated the effect of a single sucrose meal on the longevity of female and male wasps. We measured the duration of feeding, volume ingested, sucrose consumption, energy content, and longevity of wasps provided with different concentrations of sucrose (0.5, 1, and 2 M) at different times after emergence (0, 1, 2 or 3 days after emergence). Our results showed that longevity was significantly influenced by sucrose concentration and timing of feeding. For females, feeding on sucrose increased the likelihood of survival to varying degrees, ranging from 32.3% to 95.4%, compared to water-only controls. The longest duration of feeding was observed for the highest sucrose concentrations and oldest wasps. The amount of sugar ingested and energy uptake increased, up to a point, as sugar concentration increased. Our results suggest that P. lounsburyi derived greatest benefit from the intermediate concentration (1 M) of sucrose provided 2 or 3 days after emergence. Our study emphasizes the importance of finding balance between increasing longevity and limiting the duration of feeding, and concomitant uptake of nutrients, that is fundamental for survival of the wasp in nature.     

Enhancing bio-suppression of Parthenium hysterophorus L.: Diapause in Zygogramma bicolorata Pallister and its manipulation through insulin-like peptides (ILPs)

In-depth investigations on diapause behaviour of Z. bicolorata revealed that the adults entered diapause at any time from August to December and that the number peaked (42.00%) during the last half of November. The percentage of adults entering diapause increased with a decrease in day length. Weight of diapausing adults was significantly higher than weight of non-diapausing adults. The percentage of adults undergoing diapause at 30 °C was significantly lower than those undergoing diapause at 15 and 25 °C. The percentage of adults burrowing increased with increasing moisture. In silty soil and soil with high organic matter, 46.7% and 49.2% of adults entered diapause, respectively, whereas in sandy soil, only 23.5% of adults entered diapause. When newly emerged beetles were exposed to 5 μg of human insulin 30/70, a significantly lower percentage of treated adults underwent diapause compared to untreated adults under both feeding and no feeding conditions. Insulin treatment also influenced the emergence period from diapause (93.92 ± 1.73 days), percent emergence (81 ± 1.54%) and fecundity/month (512.7 ± 25.38 eggs) of Z. bicolorata in treated adults as compared to untreated adults (109.05 ± 2.2, 74.00 ± 1.82 and 438.3 ± 19.33 eggs, respectively). However, there was no significant impact of insulin on adult longevity. These findings are of great utility in the biological suppression of Parthenium as it will enhance the effectiveness of this beetle through manipulation of diapause.     

Development of Neoseiulus womersleyi (Schicha) and Euseius ovalis (Evans) feeding on four tetranychid mites (Acari: Phytoseiidae,Tetranychidae) and pollen

The development of the predatory mites, Neoseiulus womersleyi (Schicha) and Euseius ovalis (Evans), feeding on four tetranychid mites (Tetranychus urticae, Tetranychus kanzawai, Oligonychus mangiferus, Panonychus citri), maize pollen or Chinese loofah pollen was studied at 25 °C. Immature stages of N. womersleyi feeding on T. urticae and T. kanzawai had shorter developmental duration (4.71 and 5.02 days for females, 4.77 and 5.19 days for males, respectively) than those feeding on other food sources. Immature stages of E. ovalis females feeding on O. mangiferus and T. urticae developed in 4.99 and 5.13 days, respectively, the shortest developmental duration measured. Immature stages of E. ovalis males feeding on O. mangiferus and T. urticae developed in 5.12 and 5.37 days, respectively. The longevity of N. womersleyi males (13.31 to 14.51 days) and females (17.67 to 21.81 days) feeding on T. urticae, T. kanzawai or maize pollen was longer than the longevity of N. womersleyi feeding on O. mangiferus, P. citri or loofah pollen. E. ovalis males (12.91 to 16.74 days) and females (16.24 to 23.77 days) feeding on O. mangiferus, T. urticae or maize pollen lived longer than E. ovalis males and females feeding on T. kanzawai, P. citri or loofah pollen.     

The effect of diet on longevity,fecundity, and the sex ratio of Clitostethus arcuatus (Rossi) (Coleoptera: Coccinellidae)

Clitostethus arcuatus is a major, cosmopolitan predator of some Aleyrodidae. Field collected adult beetles were reared in the laboratory on different diets: Siphoninus phillyreae eggs, Trialeurodes vaporariorum eggs, Sitotroga cerealella eggs, or an artificial diet consisting of honey, yeast, and pollen. All experiments were conducted at 25 ± 2 °C, 65 ± 5% RH and a photoperiod of 16:8 (L:D) h. Female and male C. arcuatus consumed a mean (± SE) of 61 ± 0.6 and 27 ± 0.9 T. vaporariorum eggs d^? 1, respectively, and a mean of 56 ± 2.2 and 29 ± 1.1 S. phillyreae eggs d^? 1, respectively. Significant differences were noted between sexes and between hosts consumed by female C. arcuatus. No feeding occurred on S. cerealella eggs. Although there was a significant difference between rates of oviposition due to diet, fertility rates on different diets did not show significant differences. The sex ratio of C. arcuatus (female:male) was 51.4:48.6, 55.2:44.8, and 54.6:45:4 when adults fed on T. vaporariorum, S. phillyreae, and artificial diet, respectively. These differences were not significantly different. Average longevity (± SE) was 66.4 ± 2.6, 54.9 ± 2.5; 77.3 ± 6.9, 67.5 ± 7.2; and 86.4 ± 4.5 70.3 ± 3.6 days for female and male C. arctuatus, respectively, on T. vaporariorum, S. phillyreae and artificial diet, respectively, with significant differences between sexes and diets. Although developmental duration on T. vaporariorum was longer than ash whitefly, this difference was not significant (mean 27.68 ± 0.31 and 25.09 ± 0.21 days for predators reared on T. vaporariorum and S. phillyreae, respectively). Given its longevity and fecundity on T. vaporariorum, C. arcuatus may be a good choice for mass release on glasshouse crops infected by greenhouse whitefly.     

Temperature-driven models of Aculops pelekassi (Acari: Eriophyidae) based on its development and fecundity on detached citrus leaves in the laboratory

This study was carried out to develop temperature-driven models for immature development and oviposition of the pink citrus rust mite Aculops pelekassi (Keifer). A. pelekassi egg development times decreased as the temperature increased, ranging from 6.6 days at 16 °C to 1.9 days at 35 °C. Total nymph development times decreased from 8.2 days at 16 °C to 3.3 days at 35 °C. The egg-to-adult development durations were 14.8, 11.6, 9.7, 8.0, 7.3, 6.1, and 5.2 days at 16, 20, 24, 26, 28, 32, and 35 °C, respectively. The lower developmental threshold temperatures for eggs, nymphs, and total egg-to-adult development were calculated as 9.3, 4.3, and 6.9 °C, respectively. The thermal constants were 54.0, 101.8, and 153.8 degree days for each of the above stages. The non-linear biophysical model fitted well for the relationship between the development rate and temperature for all stages. The Weibull function provided a good fit for the distribution of development times of each stage. Temperature affected the longevity and fecundity of A. pelekassi. Adult longevity decreased as the temperature increased and ranged from 24.2 days at 16 °C to 14.6 days at 35.0 °C. A. pelekassi had a maximum fecundity of 33.1 eggs per female at 28 °C, which declined to 18.8 eggs per female at 16 °C. In addition, three temperature-dependent components for an oviposition model of A. pelekassi were developed with sub-models estimated: total fecundity, age-specific cumulative oviposition rate, and age-specific survival rate. The oviposition model, coupled with the stage emergence model, should be useful to construct a population model for A. pelekassi in the future.     

Oviposition model of Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae)

The longevity and fecundity of Cnaphalocrocis medinalis were investigated at temperatures of 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 32.5, and 35.0 °C. Adult longevity and fecundity were significantly influenced by temperature. Longevity decreased with increasing temperature: it was highest at 15.0 °C (23.6 ± 3.51 days) and lowest at 35.0 °C (6.4 ± 0.48 days). Fecundity was highest at 25.0 °C (170.5 ± 45.54 eggs) and lowest at 17.5 °C (11.0 ± 3.68 eggs). The oviposition period was longest at 20.0 °C (8.0 ± 1.09 days) and shortest at 35.0 °C (2.3 ± 0.48 days). The oviposition model presented in this study consisted of two reproductive components (total fecundity and age-specific cumulative oviposition rate) and a survival component (age-specific survival rate). The relationship between adult developmental rate and temperature was described by the Lactin 2 model (r² = 0.98, p < 0.0001). The age-specific survival rate was well explained by a sigmoid function (r² = 0.97, p < 0.00001). The age-specific cumulative oviposition rate was best described by the three-parameter Weibull function (r² = 0.99, p < 0.00001). Temperature-dependent fecundity was estimated using the Briere-2 model (r² = 0.94, p < 0.007). Daily egg production of C. medinalis in relation to adult age and temperature was estimated.     

Pollination ecology of Acacia gerrardii Benth. (Fabaceae: Mimosoideae) under extremely hot-dry conditions

Talh trees (Acacia gerrardii Benth.) are acacias that are native to the arid and semiarid Africa and west Asia. We investigated the flowering biology, pod set and flower visitors of Talh and discussed the role of these visitors in pollen transfer. The Talh trees blossomed laterally on the nodes of one-year-old twigs. Each node produced 21 flower buds seasonally. Each flower bud opened to a flower head (FH) of 60 florets. The bagged FHs podded significantly (p ⩽ 0.05) less than did the unbagged FHs. The FHs were visited by 31 insect species (25 genera, 16 families and 5 orders). The major taxa were honeybees, megachilids, butterflies, ants, beetles and thrips. Each of honeybees, megachilids and beetles showed a significant (p ⩽ 0.05) hourly pattern, while each of butterflies, ants and thrips had no hourly pattern (p > 0.05). Furthermore, some birds and mammals touched the Talh FHs. Talh trees evolved a mass flowering behavior to face pre- and post-flowering obstacles. Megachilids seemed to play the major effort of zoophily because of their relatively high numbers of individuals and species and their effective movement behavior on the FH surface. Nevertheless, honeybees and other insects and vertebrate taxa also contributed to the pollen transfer. These results greatly contribute to our understanding of the pollination ecology of acacias, especially Arabian acacias.     

Selective flowers to enhance biological control of cabbage pests by parasitoids

Habitat management is an important element in sustainable agriculture and can be used to maximize a range of ecosystem services that support crop production. An important example of such ecosystem services is biological control of pests which can be enhanced by providing arthropod natural enemies with suitable floral resources. The potential risk of this approach, however, is that flowering plants may enhance the fitness of the targeted pests as well. We conducted experiments to identify selective plant species that would improve the longevity and parasitization rate of the parasitoid wasp Microplitis mediator without benefiting its host pest, the cabbage moth Mamestra brassicae. Effects on longevity were also assessed for Diadegma fenestrale, a generalist parasitoid wasp attacking lepidopteran pests. Additionally, we compared the effects of floral and extrafloral nectar, the latter being formed in some plant species and can significantly prolong the duration of nectar availability for natural enemies. Longevity of M. mediator and D. fenestrale as well as parasitization rates of M. mediator were significantly increased by the presence of Fagopyrum esculentum (floral nectar), Centaurea cyanus (floral and extrafloral nectar) and non-flowering Vicia sativa (extrafloral nectar). M. mediator parasitized 202.3 ± 29.7 M. brassicae larvae during its lifetime when presented F. esculentum, compared to 14.4 ± 3.4 larvae in the absence of floral resources. Extrafloral nectar of C. cyanus and V. sativa was as suitable for M. mediator as floral nectar and significantly increased longevity and parasitization rates. Longevity and fecundity of M. brassicae were not supported by the plant species tested. These results stress the importance of plant screening to achieve plant selectivity and to maximize biological control. F. esculentum, C. cyanus and V. sativa are recommended as selective plant species to enhance parasitoids of M. brassicae.     

Feeding and oviposition preference of the Sakhalin pine sawyer Monochamus saltuarius (Coleoptera: Cerambycidae) for various tree species

Monochamus saltuarius was recently identified as an important vector of Bursaphelenchus xylophilus, the cause of pine wilt disease. In this study, M. saltuarius adults preferred different species of tree based on the longevity, ingested amount and wounded area that were determined for 90 d. Among eight tree species, the longevity of feeding by M. saltuarius was not significantly different except when feeding in Sciadopitys verticillata. However, the highest ingested amounts with the largest wounded areas were associated with Pinus koraiensis. The highest oviposition preference was in P. densiflora for the first 20 d. However, after 40 d, the oviposition highest preference was noted in P. koraiensis. For oviposition activities, M. saltuarius preferred the tree species in the following order: P. densiflora > P. koraiensis > P. rigida > Larix leptolepis. Although many oviposition scars were observed, M. saltuarius laid fewer eggs in P. rigida than other species of pine, which was related to the bark thickness. The oviposition frequencies were highest with bark 2.0–2.5 mm thick and with tree diameters of 110–130 mm. The current study increased understanding of the ecology of M. saltuarius by identifying specific tree preferences.     

Kinetic and thermodynamic analysis of the inhibitory effects of maltose,glucose, and related carbohydrates on wheat β-amylase

Inhibition of wheat β-amylase (WBA) by glucose and maltose was studied by kinetics and thermodynamics. The inhibitory effects of fructose, difructose, sucrose, trehalose, cellobiose, acarbose, and 1-deoxynojirimycin on WBA were also evaluated. The half maximal inhibitory concentrations (IC₅₀) of acarbose, maltose and glucose were 0.06 ± 0.01 M, 0.22 ± 0.09 M, and 1.41 ± 0.17 M, respectively. The inhibitor constant (K_i) and the thermodynamic parameters such as changes in Gibbs energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of the dissociation reactions of the WBA-glucose and WBA-maltose complexes were temperature and pH-dependent. The dissociation reactions were endothermic and enthalpy-driven. Both glucose and maltose behaved as competitive inhibitors at pH 3.0 and 5.4 at a temperature of 25 °C with respective K_i values of 0.33 ± 0.02 M and 0.12 ± 0.03 M. In contrast, both sugars exhibited uncompetitive inhibition at pH 9 at a temperature of 25 °C with K_i values of 0.21 ± 0.03 M for glucose and 0.11 ± 0.04 M for maltose. The pH-dependence of the inhibition type and K_i values indicate that the ionizing groups of WBA influence drastically the interaction with these carbohydrates. This evidence enables us to consider temperature and pH in the WBA-catalyzed hydrolysis to manipulate the inhibition by end-product, maltose, and even by glucose.     

Timing of onset of evening activity of adult Chinese rose beetles (Coleoptera: Scarabaeidae)

Adult Chinese rose beetles, Adoretus sinicus (Burmeister) (Coleoptera: Scarabaeidae: Adoretini), present in China, Taiwan, Indonesia, Cambodia, Laos, Singapore, Thailand, Vietnam, the Marianas Islands, the Caroline Islands, and the Hawaiian Islands, are nighttime defoliators that feed on a wide variety of plant species. It has recently been demonstrated that illumination of plants at dusk has the potential to discourage feeding by adult Chinese rose beetles on the illuminated plants. To effectively use lighting to minimize defoliation of host plants, it is critical to know the timing of the initial host plant colonization by the beetles to ensure that illumination is initiated before host plant colonization begins. Adult Chinese rose beetles were observed to colonize host plants at dusk, with initiation of beetle colonization averaging more than 21 min after sunset, with the earliest observed beetle colonization occurring 11 min after sunset. These times corresponded to an average light level of 7.0 lux at the first colonization and the earliest first colonization occurring at 26.9 lux. Based on these results, use of lighting to minimize defoliation of host plants should be initiated at about sunset in order to discourage colonization (and associated defoliation) by adult Chinese rose beetles.     

Oestrus cycle characteristics and prediction of ovulation in Catalonian jennies

The Catalonian donkey breed is in danger of extinction, and much needs to be learned about the reproductive features of its females if breeding and conservation programmes are to be successful. This study reports the oestrous behaviour, oestrus cycle characteristics and dynamic ovarian events witnessed during 50 oestrous cycles (involving 106 ovulations) in 10 Catalonian jennies between March 2002 and January 2005. These jennies were teased, palpated transrectally and examined by ultrasound using a 5 MHz linear transducer—daily during oestrus and every other day during dioestrus. Predictors of ovulation were sought among the variables recorded.The most evident signs of oestrus were mouth clapping (the frequent vertical opening and closing of the mouth with ears depressed against the extended neck) and occasional urinating and winking of the vulval lips (homotypical behaviour). Interactions between jennies in oestrus were also recorded, including mounting, herding/chasing, the Flehmen response, and vocalization (heterotypical behaviour).Nine jennies ovulated regularly throughout the year; one had two anovulatory periods (54 and 35 days). The length of the oestrus cycle was 24.90 ± 0.26 days, with oestrus itself lasting 5.64 ± 0.20 days (mean ± S.E.M.) and dioestrus 19.83 ± 0.36 days. The incidence of single, double and triple ovulations was 55.66% (n = 59), 42.45% (n = 45) and 1.89% (n = 2), respectively. No significant difference was seen in the number of ovulations involving the left and right ovaries (52.63% [n = 70] compared to 47.37% [n = 63] respectively; P > 0.05). The mean interval between double ovulation was 1.44 ± 3.98 days. The mean diameter of the preovulatory follicle at day −1 was 44.9 ± 0.5 mm; the mean growth rate over the 5 days before ovulation was 3.7 mm/day.Data on preovulatory changes in oestrous behaviour, follicle size, follicle texture, the echographic appearance of the follicle and uterus, and uterine tone were subjected to stepwise logistic regression analysis to detect predictors of ovulation. The logit function showed the best predictors to be follicle size, follicular texture and oestrous behaviour. Certain combinations of these three variables allow the prediction of ovulation within 24 h with a probability of >75%.     

Fructanolytic and saccharolytic enzymes of Treponema zioleckii strain kT

Enzymes in the newly described rumen bacterium, Treponema zioleckii strain kT, capable of digesting Timothy grass fructan, inulin, and sucrose were identified and characterized. Two specific endolevanases and one non-specific β-fructofuranosidase were found in a cell-free extract. The molecular weight of the endolevanases were estimated to be 60 and 36 kDa, whereas that of β-fructofuranosidase, 87 kDa. The former of the specific enzymes was associated with the outer membrane, while the latter and the non-specific β-fructofuranosidase, with the periplasm or cytosol. The K_m and V_max for Timothy grass fructan degradation by endolevanase were 0.27% and 15.75 μM fructose equivalents × mg protein^?1 × min^?1, those for sucrose and inulin digestion by β-fructofuranosidase were 1.35 × 10^?3 M and 1.73 μM hexoses × mg protein^?1 × min^?1 and 1.77% and 1.83 μM hexoses × mg protein^?1 × min^?1, respectively.     

Diet selection and eating behaviour of lactating goats subjected to time restricted feeding in choice and single feeding system

This study was carried out to investigate diet selection and eating behaviour of lactating German Fawn × Hair Crossbred goats in different feeding methods and levels. Twenty German Fawn × Hair first backcross does (B₁) were allocated into 4 treatment groups (2 feeding methods single (TMR) and choice feeding × 2 feeding levels ad libitum and restricted) with 5 replicates. Restricted feeding was applied only 4 h feed allocation during day. Barley, corn, soybean meal, corn gluten meal, wheat bran and alfalfa hay were feed ingredients for single and choice feeding. Eating patterns, milk yield and composition were determined for 8 weeks. The following results were obtained: (1) the meal criteria for goats restricted single and choice-fed, ad libitum single and choice-fed were determined as 1.00 and 0.63, 12.88 and 10.23 min, respectively. (2) Ad libitum feeding increased meal size, meal length, intermeal interval, total eating duration and decreased eating rate and meal number, compared to restricted feeding (P < 0.01). Choice feeding decreased meal size (P < 0.05), meal length (P < 0.01) and increased eating rate and meal number (P < 0.01), compared to single feeding. Restricted fed goats decreased intermeal interval in single feeding compared to choice feeding (P < 0.01), but increased meal number in choice feeding (P < 0.01). (3) Ad libitum choice-fed does made a diet containing 12.79% corn, 35.41% barley, 13.21% wheat bran, 5.35% soybean meal, 1.28% corn gluten meal and 29.80% alfalfa meal while restricted choice-fed does made a diet having more corn (27.69%), corn gluten meal (5.62%) and wheat bran (16.17%) and less barley (14.37%) and soybean meal (4.51%). (4) Choice feeding decreased RUP intake (P < 0.05) without affecting milk protein, irrespective to feeding levels, while having a tendency to increase in milk yield (14.2%) and 4% FCM (8.8%). (5) Restricted feeding decreased DM, ME, ADF and NDF intakes (P < 0.05) with concomitant decreases in 4% FCM, total milk solid, ash and fat compositions (P < 0.05), irrespective to feeding methods. (6) Choice-fed goats changed their preferences for a possible synchronized nutrient intake during a daytime, as sorted barley, soybean meal and alfalfa hay from early morning to late afternoon.It could be concluded that choice-fed goats have the ability to make their diet to meet nutrient requirements and had a tendency to increase in milk yield. Restriction in feeding time resulted in lower feed intake and milk yield, although the animal changed their feed preference in favour of high quality ingredients and eating pattern with lower meal criterion and intermeal interval.     

Comparison of the life tables and predation rates of Harmonia dimidiata (F.) (Coleoptera: Coccinellidae) fed on Aphis gossypii Glover (Hemiptera: Aphididae) at different temperatures

The life histories and predation rates of the ladybird beetle Harmonia dimidiata (F.) were compared among beetles kept at 15, 20, and 25 °C. The beetles were fed on Aphis gossypii Glover and were maintained at 70 ± 10% RH and a 14:10 (L:D) h photoperiod. According to the age-stage, two-sex life table, the net reproductive rates (R₀) were 147.4, 98.7, and 62.5 offspring for beetles kept at 15, 20, and 25 °C, respectively. Additionally, we employed both the jackknife and bootstrap techniques for estimating the means, variances, and standard errors of the population parameters. The sample means of R₀ and the other population parameters obtained using the bootstrap technique fit a normal distribution, but the jackknife technique generated biologically meaningless zero values for R₀. The net predation rates were 10963, 13050, and 7492 aphids for beetles kept at 15, 20, and 25 °C, respectively. For a comprehensive comparison of predation potential, we incorporated both the finite rate and the predation rate into the finite predation rate. When both the growth rate and the predation rate were considered, our results showed that H. dimidiata is a more efficient biological control agent for A. gossypii at 20 and 25 °C than at 15 °C.     

Impact of soil mesofauna on the decomposition of two main species litters in a Pinus koraiensis mixed broad-leaved forest of the Changbai Mountains

In most terrestrial ecosystems, the majority of aboveground net primary productivity enters the decomposition system as plant litter. The decomposition of plant litter plays a critical role in regulating build up of the forest soil organic matter, releasing of nutrients for plant growth, and influencing the carbon cycling. Soil fauna are considered to be an important factor in the acceleration litter decomposition and nutrient transformations. Mechanisms of soil faunal contribution to litter decomposition include digestion of substrates, increase of surface area through fragmentation and acceleration of microbial inoculation into litter. The Pinus koraiensis mixed broad-leaved forest is one of the typical forest vegetation types in Changbai Mountain. Previously, major studies carried here were focused on climate, soil and vegetation; however, on litter decomposition and the role of soil fauna in this forest ecosystem were limited. In this paper, we conducted a litter decomposition experiment using litterbag method to explore the contribution of soil fauna on litter decomposition and provide a scientific basis for maintaining a balanced in P. koraiensis mixed broad-leaved forest in Changbai Mountains. During 2009 and 2010, we used litterbags with different mesh sizes to examine the decomposition of two dominant tree species (P. koraiensis, Fraxinus mandshurica) in studied site. The results showed that the process of litter decomposition can be separated into two apparent stages. The initial decomposition process at former six months was slow, while accelerated the final six months. The former six months (from October 2009 to April 2010) was winter and spring. There was low temperature and almost no activity of soil fauna and microbes. The final six months (from June to October 2010), decomposition rates increased. In summer and autumn, both temperature and moisture increases, abundance of soil fauna was much than before and was most active. The remaining mass of P. koraiensis was higher than that of F. mandshurica in two mesh size litterbags after 1 year decomposition, meanwhile litter in 2 mm mesh size litterbag had higher decomposition rate than that of 0.01 mm for two species litter. The Collembola, Acari, Enchytraeidae Lithobiomorpha and Diptera larvae were mainly fauna groups in the litterbags. The composition of soil fauna community was difference between P. koraiensis and F. mandshurica during litter decomposition. 24 different soil fauna groups and 1431 individual were obtained in P. koraiensis litterbags; Isotomidae, Tomoceridae and Oribatida were dominant groups; while 31 different soil fauna groups and 1255 individual were obtained in F. mandshurica litterbags; Isotomidae, Hypogastruridae Oribatida and Mesostigmata were dominant groups. The rate of litter decomposition was positively correlated with the individual and group density of soil fauna. Contribution rate to litter decomposition was 1.70% for P. koraiensis and 4.83% for F. mandshurica. Repeated measures ANOVA showed that litter species, time and soil fauna had a significant impact on the rate of litter decomposition (P < 0.05). Our results suggested that soil fauna could accelerate litter decomposition and, consequently, nutrient cycling in P. koraiensis mixed broad-leaved forest, Changbai Mountains.     

Two-sex life table and predation rate of Cybocephalus flavocapitis Smith (Coleoptera: Cybocephalidae) reared on Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae), in Taiwan

Development, survival, and fecundity of the predator, Cybocephalus flavocapitis Smith, reared on its host Aulacaspis yasumatsui Takagi, were studied at 24 °C, 70 ± 10% RH, and photoperiod of 12:12 (L:D) h under laboratory conditions. Developmental periods for egg, larval, and pupal stages were 6.4, 12.1 and 14.3 d, respectively. The mean longevity of adults was 85.1 d. Raw life history data of all individuals were pooled and analyzed according to the age-stage, two-sex life table theory. The intrinsic rate of increase (r) was 0.05 d^? 1, the finite rate of increase (λ) was 1.05 d^? 1, the net reproductive rate (R₀) was 29.1 offspring, and the mean generation time (T) was 63.3 d. When we incorporated the age-stage variability of predation rate with the two-sex life table, our results indicated that the predation rates of larvae and adults were 743 eggs and 1595 scales, respectively. The net predation rate of C. flavocapitis is 1874 scales. Additionally, we compared life table results of C. flavocapitis with those of a previous life table study on Cybocephalus nipponicus because both species are currently used for the biological control of A. yasumatsui in Taiwan.