Effect of temperature,salinity,and body length on the energy budget of Daphniopsis tibetana Sars (Cladocera: Daphniidae)

We investigated the eff ects of temperature（14,20,and 22℃）,salinity（5,10,15,20,and 25）,and body length（0.83,1.17,1.49,and 2.33 mm）on the energy budget of Daphniopsis tibetana Sars in the laboratory.The results demonstrated no diff erence in D.tibetana assimilation efficiency（AE）with values of 51.59%–56.22% at the trial temperatures.Gross growth efficiency（K1）and net growth efficiency（K2）were 28.78% and 55.71%,respectively,at 14℃.Daphniopsis tibetana energy conversion efficiency（AE,K1,and K2）was higher at salinities of 10–20,with values of 72.80%–77.31%,42.50%–50.42%,and 58.43%–65.02%,respectively.Daphniopsis tibetana energy conversion efficiency was highest when body length was 1.17–1.19 mm,with values of 83.70%–84.73%,50.11%–50.81%,and 59.13%–60.71%,respectively.The results of this study can provide a reference for large-scale cultivation use of D.tibetana in the further.

Short body length phenotype is compensated by the upregulation of nidogen family members in a deleterious nid1a mutation of zebrafish

To decode biological processes,interfering with gene functions is a widely used strategy.There are a number of ways to interfere with gene functions.For instance,small interfering RNAs（siRNAs）are used to induce mRNA degradation;morpholinos are used to block protein translation（Nasevicius and Ekker,2000）;

Growth Performance of Crocodile Fed with Chicken Intestine and Trash Fish at Smallholder Farm in Siem Reap Province,Cambodia

The experiment was conducted at the smallholder crocodile farm at Pouk district,Siem reap province,and lasted 12 months,commenced from January 1st to December 31st,2023.The CRBD(Completely Randomized Block Design),was used in 3 treatments,such as T1(fed chicken intestine only),T2(fed chicken intestine+trash fish)and T3(fed trash fish only),with 4 replications in each treatment.The block was set by gender of crocodile,male and female.The 36 of local breed crocodiles 4 months old were allocated into each replication randomly.The result found that the length of crocodile gradually increased in the first semester,then it greatly increased from or for second semester for all treatments.In addition,the final body length of crocodile was significant different among treatments(p<0.001),the treatment of T2(fed chicken intestine+trash fish)had the longest one.Body length was also affected by gender,and male crocodile had longer body length(p<0.001).However,there were no significant differences for the interaction between types of feed with gender(p>0.05)(Table 1).The body weight of crocodile had gradually increased in the first semester,then it greatly increased from or for second semester for all treatments,while the final body weight of crocodile was also significant different among treatments(p<0.001)and the gender of crocodile(p<0.001).The average ADG(Daily Weight Gain)was significant different among treatments(p<0.001).Treatment of T2(fed chicken intestine+trash fish)had highest ADG,11.05 g,followed by T3(fed trash fish only),while the T1 had the lowest one.The gender of crocodile affected the ADG of crocodile,and male crocodile had higher ADG than female crocodile(p<0.001).However,there were no significant differences for the interaction between type of feed with gender(p>0.05).Feed intake was calculated based on amount of feed offer and measured in fresh basis.The amount of intake feed in all treatments was the same.FCR(Feed Conversion Ratio)was significant different among treatments(p<0.001)and also gender of crocodile(p<0.001).However,there were no significant differences for the interaction between types of feed with gender(p>0.05).In conclusion,the uses of trash fish and chicken intestine are an alternative feed source for crocodile to result in higher growth performance of crocodile.

Parametric Research of Experiments on a Carangiform Robotic Fish

In this paper, a carangiform robotic fish with 4-DoF （degree of freedom） tail has been developed. The robotic fish has capability of swimming under two modes that are radio control and autonomous swimming. Experiments were conducted to investigate the influences of characteristic parameters including the frequency, the amplitude, the wave length, the phase difference and the coefficient on forward velocity. The experimental results shown that the swimming performance of the robotic fish is affected mostly by the characteristic parameters observed.

Migration and population structure characteristics of the small yellow croaker Larimichthys polyactis in the southern Yellow Sea

Monthly fishery survey data of the small yellow croaker Larimichthys polyactis in the southern Yellow Sea from2003 and 2013 were employed to evaluate the variation in the resource distribution and biological characteristics（especially body length and sex ratio） in the population on a decadal scale.The results indicated that the small yellow croaker migrated from the Shawai fishing ground to the Dasha fishing ground in spring and was mainly distributed in the central and western parts of the Dasha fishing ground in April and May.Larimichthys polyactis in the Dasha fishing ground migrated eastward to offshore wintering grounds in autumn and reached the central Dasha fishing ground in October and November.The small yellow croaker entered the western waters of the Shawai fishing ground in winter.A large number of age 0＋ fish occurred in the Shawai and Jiangwai fishing grounds in October of 2003 and 2013.The body lengths of the spawning stock and wintering stock in 2013 were larger than those in 2003,and the monthly sex ratios（female to male） were significantly less than 1 in both years.The monthly distribution of this fish in the southern Yellow Sea was consistent with a previous finding that ＂the stock migrated between the wintering grounds in the west of Jeju Island and the Lüsi spawning grounds＂ but tended to move more northward,with the spawning grounds extending outward.In the past decade,body length variation experienced a decline after an increase,rather than a steady decrease.The sex ratio in the single-stick stow net showed a tendency to increase over the decade,but was either less than or more than 1 depending on the fishing gear;therefore,further studies should be conducted to determine the sex structure.

Regulation of water quality and growth characteristics of indoor raceway culture of Litopenaeus vannamei

Two modes of regulating the water quality of experimental ponds in indoor raceway culture of Litopenaeus vannamei were evaluated using simple water treatment facilities. A self-made water purifying net, aeration stone, composite microbe preparation, and Ceratophyllum demersum were placed in the experimental ponds and the culture water was circulated along the raceway inside the pond using a paddle wheel aerator. In addition, the water quality in the experimental pond was improved by draining effluent from the pipeline at the bottom of ponds 7 and 8 （mode I） and exchanging the circulating water in pond 10 （mode Ⅱ） with the reservoir water in pond 9 using a pump and pipeline. The water quality in the experimental ponds was similar in response to regulation using mode Ⅰ or mode Ⅱ. Water quality parameters in the experimental ponds were controlled within a suitable range by simple facilities during culture period without using any chemical treatments. The rich content of dissolved oxygen was maintained by the circular flow and continuous aeration of the pond water. The respective average values of the main water parameters in experimental ponds 7 and 10 in response to regulation of the water quality using modes Ⅰ and Ⅱwere as follows： pH 8.17 and 7.99; DO 5.16 mg/L and 5.97 mg/L; CODMn18.45 and 12.61 mg/L; TAN （NH3-N） 0.854 mg/L （0.087 mg/L） and 0.427 mg/L （0.012 mg/L）; NO2-N 0.489 mg/L and 0.337 mg/L. Moreover, the average body length and body weight of harvested shrimp of pond 7 and pond l0 were 7.56 cm and 8.99 cm, 5.10 g and 8.33 g, respectively. Furthermore, the survival rate, average biomass yield and average condition factor of the shrimp harvested were 70% and 60%, 2.54 kg/m2 and 2.14 kg/m2, and 0.675 g/cm and 0.927 g/cm, respectively. Linear equations describing the relationship between body length and culture time and cubic or power functions describing the relationship between body weight and body length were obtained based on evaluation of the growth data of shrimps throughout the culture period.

Mating behavior and sexual selection in a polygamous beetle

Mating behavior and sexual selection in relation to morphometric traits in a polygamous beetle, Glenea cantor （F.） （Coleoptera： Cerambycidae）, were investigated. Upon encounter, a male approached a female, mounted her, grasped her terminal abdomen with his hind tarsi, and attempted to mate. Successful mating lasted about 3.5 h. Although all traits measured in females and half of traits in males were significantly correlated with mating success, the primary selection on virgin females was the genital trait, thebursa copulatrix length, and that on males was the body length and hind tarsal length. Longer bursa copulatrix accommodated a larger ejaculate, suggesting that this female trait benefits the male that first mates with the female in terms of in- creasing ejaculate size to beat subsequent males in sperm competition. Under a female-biased sex ratio, more than 20% of mat- ings failed within 20s after the male genitalia had been inserted into hers, suggesting that males assess genital features of the re- ：male before insemination and undertake cryptic male mate choice. Larger males were more capable of grasping females and achieving mating. During the premating struggle the male almost always used his hind tarsi to lift the female terminal abdomen to the position for his genitalia to insert, and as a result, males with longer hind tarsi achieved higher mating success [Current Zoolo- gy 59 （2）： 257-264, 2013].

Methionine as a methyl donor regulates caste differentiation in the European honey bee(Apis mellifera)

Nutrition contributes to honey bee caste differentiation,but the role of individual nutrients is still unclear.Most essential amino acid contents,except that of methionine(Met),are greater in royal jelly than worker jelly.After〜3.5 i the Met content in the latter was slightly greater than in the former.Met is the major raw material used in the synthesis of S-adenosyl-L-methionine,an active methyl donor for DNA methylation,which is an epigenetic driver of caste differentiation.Here,we tested whether Met regulates caste differentiation in honey bees by determining its effects on the caste development of bees receiving four diets:the basic,basic+0.2%Met,basic+0.2%Met+20 mg/kg 5-azacytidine,and basic+20 mg/kg 5-azacytidine.The presence of Met decreased the adult bee body length and the numbers of ovarioles,indicating that Met may direct the development of female larvae toward worker bees.The upregulated expression of SAMS,Dnmtl,and Dnmt3 caused by Met exposure in 4-d-old larvae indicated that the worker-inductive effects of Met may occur through the promotion of DNA methylation.We investigated the co-effects of Met and glucose on bee development,and found that the effects of an increased glucose level on the number of ovarioles and body length did not strengthen the worker-inductive effects caused by Met.Our results contribute to caste development theory and suggest that Met-as a methyl donor一plays a regulatory,but not decisive,role in caste differentiation.

Toxicity of lead pollution to the collembolan Folsomia candida in Ferri-Udic Cambosols

Toxic effect of lead(Pb) pollution on Collembola in soils has seldom been studied in depth, which is especially true for growth responses since the juveniles are very small and numerous. A single species test was conducted using the collembolan Folsomia candida as the indicator species, and soil Pb pollution(at Pb concentrations of 0, 300, 600, 1 200, 2 400, and 4 800 mg kg^(-1)) was simulated by mixing Pb(NO_(3))_(2) with a natural unpolluted soil. Adult survival, reproduction, body length, and body Pb concentration were determined. Adult survival and reproduction started to decrease at soil Pb concentrations of 1 200 and 600 mg kg^(-1), respectively. Lead concentrations in adult and juvenile bodies increased with increasing Pb concentration in soil. The percentage and individual abundances based on body length analysis showed that the larger adults(2.1–2.6 mm, P < 0.01) were more sensitive to soil Pb concentration than the intermediate(1.9–2.1 mm, P < 0.001) and smaller(1.7–1.9 mm, P < 0.001) adults. Similarly, the larger juveniles(1.0–1.4 mm, P < 0.001) were more sensitive to soil Pb concentration than the intermediate(0.6–1.0 mm, P < 0.001) and smaller(0.3–0.6 mm, P < 0.001) juveniles. For both adults or juveniles, the abundance and percentage of larger individuals declined significantly with increasing soil Pb concentration, suggesting that larger individuals were more sensitive to soil Pb pollution. Therefore, body length features, especially the percentage and abundance of larger individuals, would be potential bio-indicators of soil Pb pollution and possibly other types of soil pollution.

Roll Flattening Analytical Model in Flat Rolling by Boundary Integral Equation Method

In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening calculation based on semi infinite body model, especially near the two roll barrel edges, a new and more accurate roll flattening model is proposed. Based on boundary integral equation method, an analytical model for solving a finite length semi infinite body is established. The lateral surface displacement field of the finite length semi-infinite body is simulated by finite element method （FEM） and lateral surface displacement decay functions are established. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distribu ted force is obtained and an accurate roll flattening model is established. Different from the traditional semi-infinite body model, the matrix form of the new roll flattening model is established through the mathematical derivation. The result from the new model is more consistent with that by FEM especially near the edges.

Plate Shape Control Theory and Experiment for 20-high Mill

Roll flattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the accuracy of roll flattening calculation for 20-high mill, a new and more accurate roll flattening model was proposed. In this model, the roll barrel was considered as a finite length semi-infinite body. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distributed force was obtained and an accurate roll flattening model was established. Coupled with roll bending model and strip plastic deformation, a new and more accurate plate control model for 20-high mill was established. Moreover, the effects of the first intermediate roll taper angle and taper length were analyzed. The tension distribution calculated by analytical model was consistent with the experimental results.