Insect social behavior and evolution: Research in our lab centers on the behavior, ecology, and evolution of social insects, with an emphasis on termites. Termites (Order Blattodea) evolved eusociality 50 million years earlier than social species in Hymenoptera (ants, bees, wasps), and they are a classical and important group for understanding the evolution of eusociality. We apply integrative approaches combining perspectives from chemical ecology and genetics. Big questions of interest include:

• What are the social cues in behavioral and developmental modulation?
• What are the molecular mechanisms in perception and processing of social information?
• How do pheromone, behavior, and regulatory mechanisms evolve in the cockroach-termite lineage?

Urban entomology: In addition to the fascinating nature of social insects, termites are also known for the economic importance of being highly costly and destructive structure pests. As a laboratory of urban entomology, we study the biology and management of termites and other household and structural pests, with the goals of understanding various factors affecting their function and behavior, and developing integrated pest management strategies.

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CURRENT PROJECTS

Termite chemosensation
Social evolution is integrated with the evolution of chemical communication, which is the oldest and the primary form of communications and plays an essential role in regulating fundamental behaviors. However, little is known about how chemicals are perceived in the peripheral sensory system and how chemosensory information is processed in the brain of termites. We integrate microscopic and transcriptomic approaches to characterize the chemosensory system in termites, including illustration of antennal sensilla and brain organization in different castes, and investigation of the spatial-temporal expression of chemosensory related genes. This information lays the foundation for both mechanistic studies of chemical perception and comparative studies of chemosensation across insect taxa.

Foraging behavior in subterranean termites
Subterranean termites present unique evolutionary history, ecological niches, and economic importance. They are wood-feeding insects that nest underground and construct extensive tunnels in soil to explore for food. The foraging behavior is a collective activity performed by workers in response to a variety of social and environmental conditions. While mechanisms of foraging behavior have been better understood in Drosophila and some social hymenopterans, the molecular basis of this behavior remain unknown in termites. Using the Formosan subterranean termite (Coptotermes formosanus) as a model system, we investigate the environmental/social regulation and molecular mechanisms of foraging behavior in termites.

COLLABORATIVE PROJECTS

Honey bee health (with Kate Ihle)
We are collaborating with Dr. Kate Ihle from the USDA Bee Lab to study honey bee health from the perspectives of genetics and breeding. We integrate molecular biology and chemical ecology approaches to understand mechanisms underlying queen health.

Stored rice IPM (with Blake Wilson)
We are collaborating with Dr. Blake Wilson to develop best management practices for insect pests of stored rice. This research will provide information for reducing impact of stored grain pests to the Louisiana rice industry by identifying more effective and efficient

RESEARCH PROJECTS PRIOR TO LSU

Undertaking behavior

Cannibalism or burial Undertaking behavior, the disposal of dead colony members, is a stereotypic behavior in many social insects to prevent potential pathogenic attack. Ants and honey bees carry deceased members out of the nest, but termites that feed on nitrogen-limited woody diet could benefit from recycling rather than discarding nutrients from dead nestmates. My Ph.D. research demonstrated that termites alternatively cannibalize or bury corpses based on their origin and postmortem time. They retrieve and consume freshly dead conspecifics, but bury corpses of competitive species. In addition, termites bury dead conspecifics if they are highly decomposed. Combined results from behavioral observations and brain transcriptomic profiling indicate that cannibalism is not only nutritionally beneficial, but also more energetically efficient than burial. (Watch YouTube movies for how termites manage corpses of different origins and postmortem times, and see a poster for transcriptomic analysis.)

Death cue The exploration of death cues in social insects was pioneered by E. O. Wilson in 1958. Since then, postmortem accumulation of fatty acids has been demonstrated to trigger corpse removal in several ants. As a part of my Ph.D., I identified the dynamic changes of death cues in termites. Immediately after death, the corpse releases a blend of volatiles, 3-octanone and 3-octanol, which attract live workers to retrieve and consume the bodies. The early death cue decreases quickly as the corpse decomposes. Correspondingly, the accumulation of late death cues (fatty acids, phenol, indole) elicits a behavioral switch from cannibalism to burial. The dynamic change in death cues balances nutritional rewards and pathogenic risks. This postmortem chemical communication highlights unique adaptations in termites to their ecological and social niche.

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Worker-reproductive transition

Reproductive pheromones In social organisms, individual development exhibits strong plasticity depending on the social environment. In many termite species including R. flavipes, workers are reproductively totipotent. They can differentiate into ergatoid reproductives, and continue reproduction after the death of primary queen and king. Reproductive pheromones that inhibit worker-reproductive transition have been suggested, but my study showed exciting results with evidences of both inhibitory and stimulatory substances influencing ergatoid formation. Potential sources and types of these pheromones (e.g., proctodeal fluid, cuticular hydrocarbons, and volatile substances) have been examined. This research will improve our understanding of reproductive division of labor in termites, one of the few hemimetabolous eusocial insects with bisexual colonies.

Policing behavior Reproductive conflict widely occurs in eusocial species where workers are reproductively totipotent. It is particularly true in termites during the process of reproductive succession, as conflict arises when the number of ergatoids exceeds the limit that colony can sustain. Termites resolve the conflict by killing excessive ergatoids, a previously poorly studied behavior. We addressed several questions including who kill the ergatoids, whether the attack is sex-specific, and whether it is age-dependent. Observations and experiments showed that policing behavior in R. flavipes is a concerted effort carried out by both ergatoids and workers, and the policing by ergatoids is age-dependent. Specially, older ergatoids attack younger ones, and workers are then recruited to cannibalize the injured ergatoids. This study provided the first empirical evidence of policing behavior in termites.

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Before becoming a social insect enthusiast, I studied earthworm diversity when I was a Master’s student, and Maillard reaction when I was an undergraduate at China Agricultural University in Beijing.

Ngo K, Castillo P, Laine RA, Sun Q. 2021. Effects of menadione on survival, feeding, and tunneling activity of the Formosan subterranean termite. Insects. 12(12), 1109; https://doi.org/10.3390/insects12121109

Castillo P, Le N, Sun Q. 2021. Comparative antennal morphometry and sensilla organization in the reproductive and non-reproductive castes of the Formosan subterranean termite. Insects. 12(7):576; ; https://doi.org/10.3390/insects12070576

Shi J, Zhang C, Huang S, Merchant A, Sun Q, Zhou C, Haynes KF, and Zhou X. 2021. Managing corpses from different castes in the eastern subterranean termite. Annals of the Entomological Society of America, https://doi.org/10.1093/aesa/saaa060

Sun Q, Haynes KF, Zhou X. 2021. Temporal changes in cuticular hydrocarbons during worker-reproductive transition in the eastern subterranean termite (Blattodea: Rhinotermitidae). Annals of the Entomological Society of America, https://doi.org/10.1093/aesa/saaa027

Sun Q, Hampton JD, Merchant A, Haynes KF, Zhou X. 2020. Cooperative policing behavior regulates the reproductive division of labor in a termite. Proceedings of the Royal Society B. 287(1928): 20200780. PDF

Sun Q, Haynes KF, Zhou X. 2018. Managing the risks and rewards of death in social insects. Philosophical Transactions of the Royal Society B, 373(1754), 20170258. PDF

Sun Q, Haynes KF, Hampton JD, Zhou X. 2017. Sex-specific inhibition and stimulation of worker-reproductive transition in a termite. The Science of Nature, 104(9-10): 79. PDF

Sun Q, Haynes KF, Zhou X. 2017. Dynamic changes in death cues modulate risks and rewards of corpse management in a social insect. Functional Ecology, 31(3): 697-706. PDF

Yin Z, Sun Q, Zhang X, Jing H. 2014. Optimised formation of blue Maillard reaction products of xylose and glycine model systems and associated antioxidant activity. Journal of the Science of Food and Agriculture, 94(7): 1332-1339.

Sun Q, Haynes KF, Zhou X. 2013. Differential undertaking response of a lower termite to congeneric and conspecific corpses. Scientific Reports, 3: 1650. PDF

Sun Q and Zhou X. 2013. Corpse management in social insects. International Journal of Biological Sciences, 9(3): 313-321. PDF

Sun Q, Yin Z, Jing H. 2009. Color characteristics and radical scavenging activity of four model systems of Maillard reaction between amino acids and monosaccharides. Food Science, 30(11): 118-123.

ENTM 4100 Insect Behavior (3 credits, offered fall semester, odd years)
This course provides comprehensive overview of the principles of animal behavior using insects as examples, ranging from mechanisms and functions of behavior to their ecological and evolutionary significance. We also cover recent research on insect behavior, integrative approaches for studying behavior, and how this knowledge can be applied to solve human challenges.

ENTM 7008 Special Topics in Entomology - Insect Chemical Ecology (1 credit, to be offered in fall 2022)
This course offers a fundamental introduction to insect chemical ecology, and introduces methods used to study the interaction of insects with their chemical environment. Students will have hands-on opportunities for chemical collection and behavioral analysis, and participate in discussion of recent research.

ENTM 4099 Undergraduate Entomological Research (1-3 credits, offered every semester)
We host and mentor undergraduate students to conduct independent research projects in our lab in the areas of insect social behavior, genetics, chemical ecology, or urban pest management. Students will be trained in literature review, experimental design and performance, data analysis, as well as writing and presentation of research.

Qian "Karen" Sun, PI Assistant Professor of Entomology Email: qsun@agcenter.lsu.edu Office: A511 Life Sciences Building Lab: A505/507 Life Sciences Building

Paula Castillo, Ph.D. Student (06/2018-current) Economic Development Assistantship (2019-2023) Project: Morphological and molecular characterization of termite olfactory system

Arjun Khadka, Ph.D. Student (06/2020-current) Project: Molecular basis of foraging behavior in termites

Seiji Yokota, Ph.D. Student (08/2021-current) Project: Honey bee genetics and queen health In collaboration with Dr. Kate Ihle (USDA ARS)

Joseph McCarthy, MS student (06/2019-current) Residential Life Assistantship (2019-2020) Project: Social regulation of termite foraging behavior

Steven Richardson, MS student (08/2020-current) Residential Life Assistantship (2020-2021) Project: Behavioral and physiological responses of termites to environmental stress

Kieu Ngo, Undergraduate Student (02/2021-current) LSU CoA Undergraduate Research Grant (2021-22) Biological Sciences Projects: Influence of natural and synthetic compounds on the foraging behavior of termites

Justice Rougeau, Laboratory Technician (09/2021-current) BS in Plant & Soil Systems, Louisiana State University (2021)

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LAB ALUMNI

• Nathan Le (2019-21), Undergraduate Student, Biological Sciences (recipient of LSU CoA Undergraduate Research Grant and LSU Discover Research Grant)
• Holly Boone (2020), Undergraduate Student, Wildlife Ecology
• Ryan Nguyen (2019-2020), Undergraduate Student, Biological Sciences (recipient of LSU CoA Undergraduate Research Grant)
• Jeremy Zuccaro (2018-19), Undergraduate Student, Electrical Engineering
• Michael Hom (2019), Undergraduate Student, Electrical Engineering
• Alicia Hoover (2018), Undergraduate Student, Interdisciplinary Studies

You can follow our lab at https://www.qiansunlab.com/