• Computers and Concrete
• /
• v.10 no.3
• /
• pp.295-306
• /
• 2012

Optimum cost design of a simply supported reinforced concrete beam is presented in this paper. In the formulation of the optimum design problem, the height and width of the beam, and reinforcement steel area are treated as design variables. The design constraints are implemented according to ACI 318-08 and studies in the literature. The objective function is taken as the cost of unit length of the beam consisting the cost of concrete, steel and shuttering. The solution of the design problem is obtained using the artificial bee colony algorithm which is one of the recent additions to metaheuristic techniques. The artificial bee colony algorithm is imitated the foraging behaviors of bee swarms. In application of this algorithm to the constraint problem, Deb's constraint handling method is used. Obtained results showed that the optimum value of numerical example is nearly same with the existing values in the literature.

• Korean Journal of Environmental Biology
• /
• v.27 no.4
• /
• pp.375-383
• /
• 2009

The aims of this study were wintering individuals, usage of foraging sites, potential food availability, daily activity and disturbance factors of White-naped Cranes Grus vipio on the wintering site, Han-river estuary, Goyang and Gimpo city, Korea. We want to provide basic data to conserve the cranes. Maxium population was identified 162 individuals at the middle of February in the river side and mud flat of this study area. Spring migration for breeding was started at the first week of March and finished for two weeks later. White-naped Cranes were used four feeding sites in winter; agricultural area in Hongdopyong, Yihwa-dong, Pyong-dong and Songpo-dong. Expected carrying capacity (ECC) was 334 days (121~909 days). White-naped Cranes departed from roosting site to feeding site at every morning for foraging. If they were disturbed by some factors at feeding sites, they moved to mud flat in the Han river to forage and take a rest. Daily activity was consisted of six category; feeding, alert, locomotion, preening, comfort, social and other behaviors. Feeding was the highest portion among behaviors in the wintering area. Feeding, alert, locomotion and preening in daily activities significantly differed among feeding sites. We watched total 348 times of disturbances in the wintering sites. Artificial disturbances were vehicles, humans, bicycles and motorcycles. Natural disturbances were noises, animals and others. Disturbances in all wintering sites were highest in Yihwa-dong (134 times) and followed by Hongdopyong (109 times), Songpo-dong (64 times) and then Pyong-dong (44 times). And artificial disturbances (228 times) were more than natural disturbances (120 times). Especially, vehicle was one of the most checked factor in the wintering area.

• Journal of Ecology and Environment
• /
• v.38 no.2
• /
• pp.157-162
• /
• 2015

The physical factors of Argiope bruennichi (Araneae, Araneidae) that influence the stabilimentum decoration on the web, a conspicuous white silk structure reflecting much more ultraviolet light than other spider silks in the web, have been poorly understood. In this study, individual variables involved in decorating the webs with stabilimenta by A. bruennichi were examined. The results revealed that the physical condition of the female A. bruennichi affected the behaviors of the stabilimentum decoration on the web. Among the 82 female spiders building their webs, the 49 female spiders adding upper and lower stabilimenta on their web weighed less, and had a narrower cephalothorax and shorter abdomen than the 33 female spiders that did not use stabilimentum. The heavier females decorated their webs with stabilimentum of greater widths. There were also significant positive relationships between the stabilimentum area and the female spider's cephalothorax width, and between the stabilimentum area and female spider's abdomen length. Taken together, this study suggests that spiders allocate their resources in stabilimentum decoration as a functional response to the spider's physical conditions, and also supports the "prey-attraction hypothesis," which states that the use of stabilimentum increases the foraging success by attracting more prey to the web.

• Animal cells and systems
• /
• v.9 no.1
• /
• pp.13-18
• /
• 2005

Cannibalism plays important roles at the levels of both individual and population. To enhance overall rate of successful survival and reproduction, salamander larvae may have evolved to consume both conspecifics and heterospecifics. Consuming conspecifics could result in decreased inclusive fitness possibly by killing relatives. In several salamander species, discrimination of salamander larval siblings from non-siblings and heterospecifics to avoid such a risk has been reported. To determine whether the Korean salamander larvae consume non-siblings more often than siblings and to analyze prey preferences of the salamander larvae in several different experimental conditions, a series of foraging experiments was conducted in the laboratory. We found that 1) large cannibal larvae preyed on small sibling more often than small non-sibling in a mixed group of sibling and non-sibling, 2) cannibal larvae prefered to consume live, weak, and small larvae to dead, healthy, and large larvae, and 3) cannibal larvae consumed heterospecific tadpoles more often than conspecific nonsibling larvae in a mixed group. In addition, the larval density was positively correlated with the occurrence of spacing behavior, one of the agonistic predator behaviors among salamander larvae.

• Molecules and Cells
• /
• v.46 no.7
• /
• pp.451-460
• /
• 2023

Animals generally prefer nutrients and avoid toxic and harmful chemicals. Recent behavioral and physiological studies have identified that sweet-sensing gustatory receptor neurons (GRNs) in Drosophila melanogaster mediate appetitive behaviors toward fatty acids. Sweet-sensing GRN activation requires the function of the ionotropic receptors IR25a, IR56d, and IR76b, as well as the gustatory receptor GR64e. However, we reveal that hexanoic acid (HA) is toxic rather than nutritious to D. melanogaster. HA is one of the major components of the fruit Morinda citrifolia (noni). Thus, we analyzed the gustatory responses to one of major noni fatty acids, HA, via electrophysiology and proboscis extension response (PER) assay. Electrophysiological tests show this is reminiscent of arginine-mediated neuronal responses. Here, we determined that a low concentration of HA induced attraction, which was mediated by sweet-sensing GRNs, and a high concentration of HA induced aversion, which was mediated by bitter-sensing GRNs. We also demonstrated that a low concentration of HA elicits attraction mainly mediated by GR64d and IR56d expressed by sweet-sensing GRNs, but a high concentration of HA activates three gustatory receptors (GR32a, GR33a, and GR66a) expressed by bitter-sensing GRNs. The mechanism of sensing HA is biphasic in a dose dependent manner. Furthermore, HA inhibit sugar-mediated activation like other bitter compounds. Taken together, we discovered a binary HA-sensing mechanism that may be evolutionarily meaningful in the foraging niche of insects.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.2
• /
• pp.288-296
• /
• 2001

The behavior of declawed emus in a farm environment has not been described despite its importance in the husbandry and welfare of the emu. This study examined whether declawing of emus causes chronic pain resulting in permanent changes in the locomotor and general behavior of declawed yearling emus compared to emus not declawed. One group of 40 emus were declawed on the day of hatch by removing the distal phalangeal joint using a Lyon beak-trimming machine. Another group of 40 emus not declawed were the controls. Declawed emus one year of age were allocated to a paddock $250m{\times}125m$, while the control group was placed in an adjoining paddock of the same dimensions. One hour video records of individual emus from each treatment were made from 08:00 and 17:00 h over 2 periods; firstly when food and water was available and secondly during a period when food and water was not available after being withdrawn overnight. Inactive, ingestive, posture change, grooming, aggressive and locomotor behaviors were monitored from the videotape. There was no behavioral evidence to indicate loss of locomotor ability of declawed emus or to suggest declawed emus were suffering from severe chronic pain as indicated by declawed emus engaging in significantly more bouts (p<0.05) and time of searching (p<0.05). Declawed emus also engaged in less stereotype pacing (p<0.05) indicating they were under less stress and not as frustrated as control birds which engaged in more step pushing behavior (p<0.05). Modelling analysis showed that pecking behavior in birds was most closely related to foraging behavior. Birds subject to pecking attacks demonstrated higher levels of stereotype behavior presumably as a method to cope with stress. The behavioral evidence in this study would indicate that declawing does not compromise the locomotor ability of emus and has the benefit of improving the social structure in the groups by reducing stereotype behavior and aggression.

• Animal Systematics, Evolution and Diversity
• /
• v.25 no.3
• /
• pp.325-329
• /
• 2009

Lepomis macrochirus from the family Centrarchidae, commonly known as Bluegill sunfish, is an introduced freshwater fish in Korea that thrives in lakes, ponds, reservoirs and rivers. Since its introduction into Korea in 1969, Lepomis macrochirus has rapidly dispersed out and increased in number almost all over the freshwater ecosystems in Korea. Consequently this species causes a severe ecological problem, threatening native fishes due to its omnivorous foraging behaviors upon fish juveniles and many freshwater invertebrates. To address population genetic structure of L. macrochirus, 74 fish samples from 10 populations were collected and compared for their mitochondrial D-loop control region. As the result we found that the genetic diversity of L. macrochirus is extremely low such as resulting only four haplotypes with a few nucleotide differences among them. Analysis of molecular variance (AMOVA) revealed that the source of population genetic variation is largely retained in the comparisons among individuals within populations, while it is relatively low with slight significance at the highest hierarchical group. This distribution pattern differs from what is expected when biogeography is under the influence of natural geographic barriers such as mountain ranges in Korea. Instead the result is accord with the influential role of random spreading events facilitated by local people for aquaculture and fishing, and subsequent dispersals since its single point of introduction into Korea.

• Korean Journal of Environmental Agriculture
• /
• v.20 no.2
• /
• pp.86-92
• /
• 2001

The current study was conducted to elucidate the optimum density of free-ranging ducks in a rice-duck farming system in terms of effects on duck behavior, and growth and yield of rice plants. Four paddy fields were used for this experiment, with 6, 9, 12 and 15 birds per plot, respectively. Ducklings at eight days of age were free ranged in experimental paddy plots (4.0 a each) on the 9th day after the transplantation of rice plants. Ducks were kept in the plot for seventy days, at which point rice plants reached the earing stage. Foraging, moving, working, resting, diving and pecking behaviors of the ducks were observed two times during the experimental period. Also, rice plant growth and yield according to the density of ducks per plot were examined. The foraging and moving behavior of free-ranging ducks in paddy fields for 12 hours during the daytime tended to be longer in the 12-bird plot, and working behavior was significantly (P<0.01) longer in the 12-bird plot than in the other three plots. The resting behavior was significantly (P<0.01) higher in the 9- and 15-bird plots than in the 12-bird plot. The frequency of moving behavior for 6 hours during the daytime in the 15-bird plot tended to be lower than that in the other three plots, but this difference was not significant. The amount of diving and pecking behavior in the 9-bird plot was significantly (P<0.05) higher than that in the other three plots, and the number of hills pecked tended to be higher with increasing of duck density. From thirty days after ducks were introduced to the paddy fields, the length of rice plants tended to be significantly (P<0.05) shorter in high free-ranging density plots as compared to low free-ranging density plots. The number of tillers per hill was not affected by the free-ranging density. The culm length of rice plants was significantly (P<0.05) shorter in the 12- and 15-bird plots than in the other two plots, however, the duck free-ranging density did not affect panicle length. The dry weight of the root of rice plants was increased with high free-ranging density, but there was no such increase in the top parts of the rice plants. The percent of rice plants badly damaged by free-ranging density tended to be lower in the order of 12-, 9-, 6- and 15-bird plots. The number of ears, ripening grains and crop yield per hill of rice plants in the 12-bird plot were significantly (P<0.05) higher than those of the other three plots. Therefore, the yield of each rice plant per 10 a was significantly increased in the 12-bird plot.

• Journal of Wetlands Research
• /
• v.12 no.1
• /
• pp.41-49
• /
• 2010

Web building of the spider is an investment behavior for prey foraging with genetic constraint. Individual's decision-making on the web construction depends on diverse environmental variables. This study investigated web structure of the wasp spider, Argiope bruennichi, to compare individual's behaviors in dry field and in wet field. We measured 35 web structures in dry field (Chunma-San, Incheon) showing relatively low humidity (46.4%) and luxuriant herbage, and 13 web structures in the wet rice field (73.9%; Taean-Gun, Chungnam). Comparing to the wet field the individuals in the dry field invested significantly more silk: $32.5{\pm}12.8$ number of silk spirals used in the dry field vs. $16.9{\pm}5.4$ in the wet field. The web area of the dry field was greater than that of the wet field: $976{\pm}643cm^2$ vs. $532{\pm}254cm^2$. The web height, distance between the ground and the center of the web, appeared higher in the dry field than in the wet field: $71.4{\pm}39.6cm$ vs. $49.6{\pm}31.2cm$. Also the web constructed in the dry field showed longer stabilimentum than the web of the wet field: $18.8{\pm}3.4cm$ vs. $3.9{\pm}3.2cm$. The perpendicular inclination and the inclination to East-West of the web showed no difference between the two fields. This study suggests that adult females of A. bruennichi could modulate its construction behavior depending on the micro-habitat factors.

• Korean Journal of Environment and Ecology
• /
• v.27 no.3
• /
• pp.305-315
• /
• 2013

This study is aimed to provide the preliminary data for conservation and management of wintering site for Anser fabalis population in Cheongna Area, Incheon Free Economic Zone, Korea through analyzing the relationship between the biotop structure of its wintering site and behavior characteristics. The main types (size and ratio) of the biotope in Cheongna Area, Incheon Free Economic Zone are reed wetlands ($6,093,762m^2$, 47.8%), rice fields without rice straw ($2,927,916m^2$, 23.0%), and rice fields with rice straw ($1,915,655m^2$, 15.0%). According to the survey carried on 13th Feb., 2013, total 33 species and 6, 535 individual birds were observed and among of them, the dominant bird was Anser fabalis showing 5,128 indiviuals, 78% of total population. As the result of analyzing the migratory route of Anser fabalis, the bird moved from roosting site to foraging site before and after sunrise and from feeding site to roosting site before and after sunset. According to the analysis of interrelation between habitat characteristics and biotope types of the bird, population density was the highest in reed wetlands among habitat types and individual appearance was the highest in water-filled rice field melting ice. The bird ate the roots and bulb of hydrophytes in reed wetlands and showed various behaviors like eating dropped grains, resting and sleeping in water-filled rice fields and eating dropped grains and resting in rice fields with and without rice straw. It is shown that the number of Anser fabalis appearing in rice fields is depended on the presence of dropped grains than types of rice field.