The two sibling species of fruit fly, Drosophila melanogaster and D. simulans (Diptera: Drosophilidae), have long been used as the key model organisms in ecological and evolutionary research. While numerous studies have investigated the thermal responses of these two species, no study has yet systematically compared their response to dietary macronutrient balance. To fill this knowledge gap, we compared how various life-history traits expressed during larval development would response to an array of dietary ratio of protein to carbohydrate (P:C ratio) in these two sibling species. Largely consistent with previous studies, D. melanogaster took longer to complete their larval development and were much larger at adult emergence than D. simulans. For both species, an increase in dietary P:C ratio resulted in improved larval survivorship and faster development. However, the two species showed qualitatively different response to dietary P:C ratio when body mass at adult eclosion was concerned. The body mass of D. melanogaster peaked at an optimal P:C ratio of 1:4, but decreased as the P:C ratio either increased or decreased from this optimum. In marked contrast, the body mass of D. simulans was insensitive to dietary P:C ratio.

The habitat of Drosophila melanogaster is the environment of fruit decay/fermentation which emits high concentrations of chemicals. Our recent studies revealed that D. melanogaster has been evolutionarily adapted to its habitat through tolerance to chemicals and induction of antimicrobial peptides (AMPs) plays an important role for chemical tolerance. To determine the correlation between AMPs and the chemical tolerance pathway, we hypothesized that expression of AMPs is induced by tissue damages or ROS caused by chemical exposure and AMPs activate antioxidant enzymes, thereby inducing chemical tolerance in D. melanogaster. Therefore, in this study, we investigated the induction levels of genes associated with necrosis (EGR and BSK), apoptosis (Dronc, Dcp1, and Drice), antioxidant physiology (SOD1, SOD2, CAT, Trxr1, GstD2, and GstD5), and SAM metabolism (Gnmt and Foxo) in D. melanogaster exposed to three chemicals, 2-phenylethanol, ethanol, and acetic acid. As a result, above genes were induced in chemical-exposed fly, and this supports our hypothesis of chemical tolerance pathway in D. melanogaster.

동물의 종 유지에 있어서 교미행동은 매우 중요한 위치를 차지함. 교미과정에서 수컷의 경우 모든 암컷에 대해 성행동을 보이는반면, 암컷은 가장 적절한 교미의 시기를 정하며, 적절한 수컷을 선택하고 교미행동을 보이기 때문에 암컷의 교미행동을 유도하는 과정은 생물학에서 매우 중요한 의미를 지님. 본 연구에서는 초파리 (Drosophila melanogaster) 전자현미경자료와 총신경망분석 (Connectomics)을 이용하여 초파리 뇌에서 암컷의 교미행동을 조절하는 것으로 알려진 pC1신경의 하부신경 pC1b,c가 성적 성숙과정에서 교미를 하고자 하는 욕구 (sexual drive)를 증가시키는 기능을 하는 것을 처음으로 밝힘. 본 연구에서는 처음으로 pC1b,c 신경 내의 cAMP 수준이 교미의 욕구변화를 보여주는 중요한 물질이라는 것을 밝혔고 cAMP의 수준이 오르기 위해서는 신경펩티 드인 Dh44와 그 수용체 GPCR인 Dh44R1과 Dh44R2가 필요하다는 것을 확인함. 또한 cAMP의 변화는 신경내의 CREBB를 통하여 하위 유전자인 pyx (pyrexia)의 발현을 유도한다는 것을 밝힘. 본 연구로 종 유지 메커니즘을 좀 더 이해할 수 있음.

From invertebrate to vertebrate, females uptake sperm for a specific duration post-copulation known as the ejaculate holding period (EHP) before expelling un-stored sperm and the mating plug through sperm ejection. Our study uncovered that encountering males or mated females after mating substantially shortens EHP, a phenomenon we term ‘male-induced EHP shortening (MIES)’. MIES requires Or47b+ olfactory and ppk23+ gustatory neurons, activated by 2-methyltetracosane and 7-tricosene, respectively. These odorants raise cAMP levels in pC1b and c neurons, which are responsible for processing male courtship and regulating female receptivity. Elevated cAMP levels in pC1b and c reduce EHP and reinstate their responsiveness to male courtship cues, promoting re-mating with faster sperm ejection. This study establishes MIES as a genetically tractable model of sexual plasticity with a conserved neural mechanism.

Salt is crucial for survival, yet excessive intake of sodium chloride can have adverse effects. In the fruit fly, Drosophila melanogaster, internal taste organs located in the pharynx play a pivotal role in determining whether to accept or reject food. However, our understanding of how pharyngeal gustatory receptor neurons (GRNs) perceive high salt levels is still limited. In this study, we discovered that a specific member of the ionotropic receptor family, Ir60b, is selectively expressed in a pair of GRNs that respond to high salt concentrations. Through a two-way choice assay (DrosoX) to measure ingestion volume, we established that IR60b, along with two coreceptors, IR25a and IR76b, is necessary to deter excessive salt consumption. Interestingly, mutants lacking external taste organs but retaining internal taste organs in the pharynx showed significantly higher salt avoidance compared to flies missing all three IRs while still possessing all taste organs. These findings underscore the crucial role of IRs in pharyngeal GRNs in regulating the intake of high salt levels.

Group movements of insects are bases for unravelling origin of social behavior of animals and are important in both theoretical (e.g., evolution) and practical (monitoriing) aspects. Automatic recognition and effective computational methods were developed for characterizing multi-individual interactions in laboratory conditions. Movements of Drosophila species in different genetic strains were continuously observed across days. Characteristic behaviors are objectively expressed based on parameter extraction and data structure visualization. Group activities, including aggregation, inter-individual interactions and arena positioning were objectively characterized in different photo- and scoto-phases according to machine-learning and spatio-termporal patterning techniques. Individual-group relationships are presented regarding how individual movements would contribute to formulating group activities. Usefulness of automatic monitoring of insect group movement is further discussed for a basis for genetic functioning in behavioral aspect.

Although ethylformate and phosphine fumigants are widely used for pest quarantine, studies related to their mechanism of action and metabolic physiological changes in Drosophila models are still unclear. In this study, we investigated how key metabolites altered by fumigants and cold treatment are associated with and affect insect physiology by comparative metabolome analysis. Fumigant treatment significantly altered cytochrome P450 and glutathione metabolites involved in the detoxification mechanism and showed lower expression of PGF2α involved in the immune response compared to the control. Additionally, most of the metabolites functioned in metabolic pathways related to the biosynthesis of amino acids, nucleotides and cofactors.

Drosophila suzukii (Diptera, Drosophilidae) can damage thin-skinned fruits (plums, cherries, peaches, blueberries, and strawberries) by laying eggs inside the fruit. In this study, a basic experiment was conducted to investigate the preference of D. suzukii to export table grape varieties. Four varieties of grapes (Kyoho grape, Shine muscat, Campbell grape, and Black sapphire) were placed in a cage containing more than 2,500 number of D. suzukii adults for 6, 8, 10, 12, and 24 hours and the egg-laying in grape has been induced. After 2 weeks, the number of pupae that emerged was counted. As a result, the largest number of pupae was generated in Kyoho grape among the four types of grapes, indicating that D. suzukii prefers to lay egg in Kyoho grape. Through this experiment, it was determined that 6 h was the appropriate inoculation time, and then an inoculation experiment was conducted on Kyoho grape. The total weight of the Kyoho grape used in the experiment was 36.119 kg, and a total of 2594 pupae were generated. The average number of D. suzukii per cluster was about 50. All stages of D. suzukii treated with low temperature(1℃) for 10 days were completely controlled.

해충에 이용되는 화학적 기피제는 생태계를 파괴할 수 있으며 내성을 가진 생물체로의 진화를 촉진한다. 같은 종의 생물끼리의 의사소통 수단인 페로몬을 이용하면 다른 종에게 영향을 미치지 않으면서 특정 곤충에 특이적 으로 작용하는 방충제를 제작할 수 있을 것이라 생각된다. 본 연구는 초파리(Drosophila)의 페로몬 2종류를 추출 하여 초파리의 기피도 및 유인도와 번식률을 확인하고자 한다. ℃, 광주기 12h/12h의 동일한 조건에서 사육하 며 10마리당 헥세인 10를 사용하여 암컷의 표피에서 CHC 페로몬과 수컷의 페로몬샘에서 cVA 페로몬을 추출 한다. 연령, 성별, 교배 여부에 따라 관찰통에 각각의 페로몬을 처리하여 지정구간에 분포하는 초파리의 수를 계수하여 기피도 및 유인도를 확인한다. 관병에 암수 1쌍을 투입하고 하루에 1번 선정한 페로몬을 투여하며 산란 수을 측정한다. 이 연구를 통해 CHC가 수컷 초파리에 대한 기피 효과가 있음을 확인하였으며 추출되는 수컷의 연령이 높을수록 cVA에 의한 번식률 감소가 크게 나타났다. 본 연구를 통해 페로몬을 통한 초파리의 방제 가능성 을 확인하였으므로 다른 곤충의 방제에도 적용할 수 있을 거라 기대한다. 페로몬은 생물 농축과 같은 환경적 영향이 없으며 소량으로 유의미한 결과를 도출했다는 점에서 의의가 있으며 상용화를 통해 해충에 의해 피해를 해결할 수 있을 것이라 기대한다.