Short range hunters: Exploring the function and constraints of water shooting in dwarf gouramis

Ballistic predation is a rare foraging adaptation: in fishes, most attention has focused on a single genus, the archerfish, known to manipulate water to shoot down prey above the water surface. However, several gourami species also exhibit apparently similar ‘shooting’ behaviour, spitting water up to 5cm above the surface. In a series of experiments, we explored the shooting behaviour and aspects of its significance as a foraging ability in the dwarf gourami (Trichogaster lalius). We investigated sex differences in shooting abilities as gourami shooting may be related to the sex-specific bubble nest manufacture - where males mix air and water at the surface to form bubbles - finding that actually both sexes are equally able to shoot and learn to shoot a novel target. In a second experiment, we presented untrained gouramis with opportunities to shoot at live prey and found they successfully shot down both fruit flies and crickets. Finally, we explored the effect of target height on shooting performance to establish potential constraints of shooting as a foraging ability. The frequency of attempted shots and success of hitting targets decreased with height while latency to shoot increased. We also observed that repeatable individual differences account for variation in these measures of shooting performance. Together our results provide evidence that gourami shooting has a foraging function analogous to that of archerfish. Gourami shooting may serve as an example of convergent evolution and provide opportunities for comparative studies into the, yet unexplored, ecology and evolution of shooting in fishes.

Foraging ability of maize weevil in several varieties under dark and light conditions

Laboratory research to investigate the ability of maize weevil to find food source in the dark and light condition had been conducted in laboratory of pests and plan diseases of Indonesian Cereals Research Institute, Maros, South Sulawesi. This research was arranged in complete random design with three replications. There were six maize varieties put into small glasses and placed in circle within big jar and then invested with 100 heterogenous adult maize weevils in each jar. As a control, an empty glass was put in the center of glasses circle within the jar. Observation and calculation on living and dead maize weevils on each glass and outside glass was conducted with intervals of 24, 48 and 72 after maize weevil infestation. This research was performed in the light and dark condition. Result of the research showed that maize weevil ability to find their food sources was not determined by the light and dark. In addition, from this research, it was found that there were influence of corn variety as food resources, but this factor of variety as food resources needs to be examined further. The implication of this study are about the maize varieties attracted the weevil.

Ovipositor sources for queen-rearing of honey bee (Apis mellifera) revealed inheritable maternal effect on reared queen

Queen is arguably the most important member of a honey bee colony, and queen quality is crucial for honey bee colony growth and development. In this study, queens were reared with eggs laid in queen cells (QE), eggs laid in worker cells (WE) and 2-day old larvae in worker cells (L). Those physiological indexes (the weight, thorax size and number of ovarioles) of newly reared queens in each group were measured. Moreover, the reproductive potential of the newly reared queens and foraging ability of worker bees laid by the newly reared queens in each group were further explored. In addition, we also examined whether maternal effects would be transmitted to the offspring queens in honey bee. We found that the weight, number of ovarioles and thorax weight of newly emerged queens in QE were significantly higher than those in WE and L, suggesting the reproductive potential was stronger in QE group than WE and L group. Furthermore, offspring worker bees and queens of QE queens had higher weight at emergence than those from the other two groups. This study proved profound honey bee maternal effects on queen quality, which can be transmitted to their offspring. Our results of the present study were important for improving queen quality and promoting the development of beekeeping and agriculture.

Effect of 9,12-Octadecadiynoic Acid on Neurobehavioral Development in Caenorhabditis elegans

Human breast milk lipids have major beneficial effects: they promote infant early brain development, growth and health. To identify the relationship between human breast milk lipids and infant neurodevelopment, multivariate analyses that combined lipidomics and psychological Bayley-III scales evaluation were utilized. We identified that 9,12-octadecadiynoic acid has a significantly positive correlation with infant adaptive behavioral development, which is a crucial neurodevelopment to manage risk from environmental stress. To further clarify the biological function of 9,12-octadecadiynoic acid in regulating neurodevelopment, Caenorhabditis elegans (C. elegans) was used as a model to investigate the effect of 9,12-octadecadiynoic acid on neurobehavioral development. Supplementation with 9,12-octadecadiynoic acid from the L1 to L4 stage in larvae affected locomotive behaviors and foraging ability that were not socially interactive, implying that 9,12-octadecadiynoic acid is involved in regulating the serotonergic neuronal ability. We found that supplementary 0.1 μM 9,12-octadecadiynoic acid accelerated the locomotive ability and foraging ability via increasing the expression of serotonin transporter mod-1. Antioxidant defense genes, sod-1, sod-3 and cyp-35A2 are involved in 9,12-octadecadiynoic acid-induced motor neuronal activity. Nevertheless, supplementary 9,12-octadecadiynoic acid at concentrations above 1 μM significantly attenuated locomotive behaviors, foraging ability, serotonin synthesis, serotonin-related gene expressions and stress-related gene expression, resulting in the decreased longevity of worms in the experiment. In conclusion, our study demonstrates the biological function of 9,12-octadecadiynoic acid in governing adaptive behavioral development.

Foraging behavior of the sea urchin Mesocentrotus nudus exposed to conspecific alarm cues in various conditions

Conspecific alarm cues crushed from Mesocentrotus nudus prevent sea urchins from foraging the kelp, but do not repel them far away from the kelp. However, it remains largely unknown of whether this phenomenon was affected by conspecific alarm cues or by the attraction of the kelp. The present study found no significant difference in the duration in the danger area with or without the kelp around conspecific alarm cues. This suggests that the phenomenon is the strategy of sea urchins but not by the attraction of kelp. We found that conspecific alarm cues appearing between the kelp and sea urchins significantly affected foraging behavior of sea urchins fasted for 21 days. This indicates that conspecific alarm cues can effectively prevent fasted sea urchins from foraging the kelp. Further, there was no correlation between foraging velocity and the duration in the danger area. Pearson correlation analysis revealed no significant correlation between foraging velocity and the duration in the safety area close to different amounts of conspecific alarm cues, suggesting that conspecific alarm cues prevent sea urchins with strong foraging ability to forage. Collectively, the present results indicate that conspecific alarm cues as highly available biological barriers are cost-effective approaches to preventing overgrazing of sea urchins in the protection of kelp beds ecosystems. Notably, the present study is a short-term laboratory investigation that does not consider the complexity of natural conditions. Future studies are essential to test the present findings in the field.

Visual foraging and executive functions: A developmental perspective

In the past few years, interest in visual foraging, where participants search for multiple targets at a time, has increased, as such tasks may provide a richer picture of visual attention than traditional single-target visual search tasks. Little is known about visual foraging in childhood, so we tested 67 6th grade Icelandic children (mean age = 11.80 years, SD = 0.30 years; 36 girls) on a foraging task involving multiple targets of different types, also measuring three subdomains of executive functioning: inhibition, attentional flexibility, and working memory. The foraging results were then compared to findings from a previous study on younger children (66 children aged 4-7 years). The results show that foraging ability improves dramatically between the preschool and middle school years, and that this improvement reflects greater ease with switching between target types. The older children showed foraging patterns previously seen for adults: randomly switching between target templates during feature foraging, but exhaustively foraging for a single target type before switching during conjunction foraging. Younger children, conversely, tended to stick with the same target type for long runs during feature foraging. Switch costs were also much lower for the older children, resulting in faster and more efficient foraging. Lastly, a connection was established between foraging ability and both working memory and attentional flexibility, but not inhibition. Our study shows that foraging is a promising field of study to further our knowledge of visual attention, how it changes throughout the lifespan, and how it is connected to other cognitive functions.

Root Foraging Ability for Phosphorus in Different Genotypes Taxodium ‘Zhongshanshan’ and Their Parents under Phosphorus Deficiency

The phosphorus (P) deficiency is the one of the key constraints for Taxodium ‘Zhongshanshan’ afforestation. A hydroponic experiment was conducted to explore root foraging ability for P in different genotypes of Taxodium ‘Zhongshanshan’ (T.‘Zhongshanshan’) and their parents (T.mucronatum and T.distichum). Five P levels of CK (31 mg/L), P15 (15 mg/L), P10 (10 mg/L), P5 (5 mg/L), and P0 (0 mg/L) were set up as the P deficiency stress treatment. The plant P contents, root morphological indices, and plant growth traits of different taxodium genotypes were measured. Meanwhile, the root foraging ability for P was evaluated with the membership function method in combination with weight. Results showed that: (1) Except the plant P content, the root morphology, plant net biomass, and height showed significant differences among the different genotypes (p < 0.05); the P deficiency stress had no significant influence on root morphology, but a significant influence on plant net biomass and height and P content; (2) T.mucronatum and T.‘Zhongshanshan’302 had relatively lower values of root length, root surface area, root volume, and plant net biomass, but had no difference of plant P content with the other genotypes; (3) T.mucronatum and T.‘Zhongshanshan’302 had higher root foraging ability for P than the other genotypes; (4) the stepwise regression analysis revealed the root volume as the main factor significantly influencing the root foraging ability. This study concluded that different genotypes of T.’Zhongshanshan’ and their parents had different root foraging ability for P, and breeding and screening the fine varieties is conducive for the afforestation in P-limited areas.