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Williams SB, Franklin B, Lemieux FA, Rand DM. Natural variation in starvation sensitivity maps to a point mutation in phospholipase IPLA2-VIA in Drosophila melanogaster. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.05.602254. [PMID: 39005416 PMCID: PMC11245103 DOI: 10.1101/2024.07.05.602254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Resistance to starvation is a classic complex trait, where genetic and environmental variables can greatly modify an animal's ability to survive without nutrients. In this study, we investigate the genetic basis of starvation resistance using complementary quantitative and classical genetic mapping in Drosophila melanogaster. Using the Drosophila Genetics Reference Panel (DGRP) as a starting point, we queried the genetic basis of starvation sensitivity in one of the most sensitive DGRP lines. We localize a major effect locus modifying starvation resistance to the phospholipase iPLA2-VIA. This finding is consistent with the work of others which demonstrate the importance of lipid regulation in starvation stress. Furthermore, we demonstrate that iPLA2-VIA plays a role in the maintenance of sugar reserves post-starvation, which highlights a key dynamic between lipid remodeling, sugar metabolism and resistance to starvation stress.
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Affiliation(s)
- Shawn B. Williams
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02906, USA
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
| | - Brian Franklin
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
| | - Faye A. Lemieux
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
| | - David M Rand
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
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2
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Gallman K, Rastogi A, North O, O'Gorman M, Hutton P, Lloyd E, Warren W, Kowalko JE, Duboue ER, Rohner N, Keene AC. Postprandial sleep in short-sleeping Mexican cavefish. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.03.602003. [PMID: 39005273 PMCID: PMC11244998 DOI: 10.1101/2024.07.03.602003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Interaction between sleep and feeding behaviors are critical for adaptive fitness. Diverse species suppress sleep when food is scarce to increase the time spent foraging. Post-prandial sleep, an increase in sleep time following a feeding event, has been documented in vertebrate and invertebrate animals. While interactions between sleep and feeding appear to be highly conserved, the evolution of postprandial sleep in response to changes in food availability remains poorly understood. Multiple populations of the Mexican cavefish, Astyanax mexicanus, have independently evolved sleep loss and increased food consumption compared to surface-dwelling fish of the same species, providing the opportunity to investigate the evolution of interactions between sleep and feeding. Here, we investigate effects of feeding on sleep in larval and adult surface fish, and two parallelly evolved cave populations of A. mexicanus. Larval surface and cave populations of A. mexicanus increase sleep immediately following a meal, providing the first evidence of postprandial sleep in a fish model. The amount of sleep was not correlated to meal size and occurred independently of feeding time. In contrast to larvae, postprandial sleep was not detected in adult surface or cavefish, that can survive for months without food. Together, these findings reveal that postprandial sleep is present in multiple short-sleeping populations of cavefish, suggesting sleep-feeding interactions are retained despite the evolution of sleep loss. These findings raise the possibility that postprandial sleep is critical for energy conservation and survival in larvae that are highly sensitive to food deprivation.
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Affiliation(s)
- Kathryn Gallman
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Aakriti Rastogi
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Owen North
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Morgan O'Gorman
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Pierce Hutton
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Evan Lloyd
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Wes Warren
- Department of Genomics, University of Missouri, Columbia, MO 65201
| | - Johanna E Kowalko
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | | | - Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Alex C Keene
- Department of Biology, Texas A&M University, College Station, TX 77840
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3
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Arango NK, Morgante F. Comparing statistical learning methods for complex trait prediction from gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596951. [PMID: 38895364 PMCID: PMC11185554 DOI: 10.1101/2024.06.01.596951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Accurate prediction of complex traits is an important task in quantitative genetics that has become increasingly relevant for personalized medicine. Genotypes have traditionally been used for trait prediction using a variety of methods such as mixed models, Bayesian methods, penalized regressions, dimension reductions, and machine learning methods. Recent studies have shown that gene expression levels can produce higher prediction accuracy than genotypes. However, only a few prediction methods were used in these studies. Thus, a comprehensive assessment of methods is needed to fully evaluate the potential of gene expression as a predictor of complex trait phenotypes. Here, we used data from the Drosophila Genetic Reference Panel (DGRP) to compare the ability of several existing statistical learning methods to predict starvation resistance from gene expression in the two sexes separately. The methods considered differ in assumptions about the distribution of gene effect sizes - ranging from models that assume that every gene affects the trait to more sparse models - and their ability to capture gene-gene interactions. We also used functional annotation (i.e., Gene Ontology (GO)) as an external source of biological information to inform prediction models. The results show that differences in prediction accuracy between methods exist, although they are generally not large. Methods performing variable selection gave higher accuracy in females while methods assuming a more polygenic architecture performed better in males. Incorporating GO annotations further improved prediction accuracy for a few GO terms of biological significance. Biological significance extended to the genes underlying highly predictive GO terms with different genes emerging between sexes. Notably, the Insulin-like Receptor (InR) was prevalent across methods and sexes. Our results confirmed the potential of transcriptomic prediction and highlighted the importance of selecting appropriate methods and strategies in order to achieve accurate predictions.
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Affiliation(s)
- Noah Klimkowski Arango
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Fabio Morgante
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
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Lloyd E, Rastogi A, Holtz N, Aaronson B, Craig Albertson R, Keene AC. Ontogeny and social context regulate the circadian activity patterns of Lake Malawi cichlids. J Comp Physiol B 2024; 194:299-313. [PMID: 37910192 PMCID: PMC11233325 DOI: 10.1007/s00360-023-01523-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 09/01/2023] [Accepted: 09/25/2023] [Indexed: 11/03/2023]
Abstract
Activity patterns tend to be highly stereotyped and critical for executing many different behaviors including foraging, social interactions, and predator avoidance. Differences in the circadian timing of locomotor activity and rest periods can facilitate habitat partitioning and the exploitation of novel niches. As a consequence, closely related species often display highly divergent activity patterns, suggesting that shifts from diurnal to nocturnal behavior, or vice versa, are critical for survival. In Africa's Lake Malawi alone, there are over 500 species of cichlids, which inhabit diverse environments and exhibit extensive phenotypic variation. We have previously identified a substantial range in activity patterns across adult Lake Malawi cichlid species, from strongly diurnal to strongly nocturnal. In many species, including fishes, ecological pressures differ dramatically across life-history stages, raising the possibility that activity patterns may change over ontogeny. To determine if rest-activity patterns change across life stages, we compared the locomotor patterns of six Lake Malawi cichlid species. While total rest and activity did not change between early juvenile and adult stages, rest-activity patterns did, with juveniles displaying distinct activity rhythms that are more robust than adults. One distinct difference between juveniles and adults is the emergence of complex social behavior. To determine whether social context is required for activity rhythms, we next measured locomotor behavior in group-housed adult fish. We found that when normal social interactions were allowed, locomotor activity patterns were restored, supporting the notion that social interactions promote circadian regulation of activity in adult fish. These findings reveal a previously unidentified link between developmental stage and social interactions in the circadian timing of cichlid activity.
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Affiliation(s)
- Evan Lloyd
- Department of Biology, Texas A&M University, College Station, TX, 77840, USA
| | - Aakriti Rastogi
- Department of Biology, Texas A&M University, College Station, TX, 77840, USA
| | - Niah Holtz
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA, 01003, USA
| | - Ben Aaronson
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - R Craig Albertson
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Alex C Keene
- Department of Biology, Texas A&M University, College Station, TX, 77840, USA.
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Pozo-Morales M, Cobham AE, Centola C, McKinney MC, Liu P, Perazzolo C, Lefort A, Libert F, Bai H, Rohner N, Singh SP. Starvation-resistant cavefish reveal conserved mechanisms of starvation-induced hepatic lipotoxicity. Life Sci Alliance 2024; 7:e202302458. [PMID: 38467419 PMCID: PMC10927358 DOI: 10.26508/lsa.202302458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/13/2024] Open
Abstract
Starvation causes the accumulation of lipid droplets in the liver, a somewhat counterintuitive phenomenon that is nevertheless conserved from flies to humans. Much like fatty liver resulting from overfeeding, hepatic lipid accumulation (steatosis) during undernourishment can lead to lipotoxicity and atrophy of the liver. Here, we found that although surface populations of Astyanax mexicanus undergo this evolutionarily conserved response to starvation, the starvation-resistant cavefish larvae of the same species do not display an accumulation of lipid droplets upon starvation. Moreover, cavefish are resistant to liver atrophy during starvation, providing a unique system to explore strategies for liver protection. Using comparative transcriptomics between zebrafish, surface fish, and cavefish, we identified the fatty acid transporter slc27a2a/fatp2 to be correlated with the development of fatty liver. Pharmacological inhibition of slc27a2a in zebrafish rescues steatosis and atrophy of the liver upon starvation. Furthermore, down-regulation of FATP2 in Drosophila larvae inhibits the development of starvation-induced steatosis, suggesting the evolutionarily conserved importance of the gene in regulating fatty liver upon nutrition deprivation. Overall, our study identifies a conserved, druggable target to protect the liver from atrophy during starvation.
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Affiliation(s)
- Macarena Pozo-Morales
- https://ror.org/01r9htc13 IRIBHM, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Ansa E Cobham
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Cielo Centola
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | | | - Peiduo Liu
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, USA
| | - Camille Perazzolo
- https://ror.org/01r9htc13 IRIBHM, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Anne Lefort
- https://ror.org/01r9htc13 IRIBHM, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Frédérick Libert
- https://ror.org/01r9htc13 IRIBHM, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Hua Bai
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, USA
| | - Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, MO, USA
- Department of Cell Biology & Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Sumeet Pal Singh
- https://ror.org/01r9htc13 IRIBHM, Université Libre de Bruxelles (ULB), Brussels, Belgium
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Alton LA, Kutz T, Bywater CL, Lombardi E, Cockerell FE, Layh S, Winwood-Smith H, Arnold PA, Beaman JE, Walter GM, Monro K, Mirth CK, Sgrò CM, White CR. Temperature and nutrition do not interact to shape the evolution of metabolic rate. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220484. [PMID: 38186272 PMCID: PMC10772606 DOI: 10.1098/rstb.2022.0484] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/22/2023] [Indexed: 01/09/2024] Open
Abstract
Metabolic cold adaptation, or Krogh's rule, is the controversial hypothesis that predicts a monotonically negative relationship between metabolic rate and environmental temperature for ectotherms living along thermal clines measured at a common temperature. Macrophysiological patterns consistent with Krogh's rule are not always evident in nature, and experimentally evolved responses to temperature have failed to replicate such patterns. Hence, temperature may not be the sole driver of observed variation in metabolic rate. We tested the hypothesis that temperature, as a driver of energy demand, interacts with nutrition, a driver of energy supply, to shape the evolution of metabolic rate to produce a pattern resembling Krogh's rule. To do this, we evolved replicate lines of Drosophila melanogaster at 18, 25 or 28°C on control, low-calorie or low-protein diets. Contrary to our prediction, we observed no effect of nutrition, alone or interacting with temperature, on adult female and male metabolic rates. Moreover, support for Krogh's rule was only in females at lower temperatures. We, therefore, hypothesize that observed variation in metabolic rate along environmental clines arises from the metabolic consequences of environment-specific life-history optimization, rather than because of the direct effect of temperature on metabolic rate. This article is part of the theme issue 'The evolutionary significance of variation in metabolic rates'.
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Affiliation(s)
- Lesley A. Alton
- Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Teresa Kutz
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Candice L. Bywater
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Emily Lombardi
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Fiona E. Cockerell
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Sean Layh
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Hugh Winwood-Smith
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Pieter A. Arnold
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Julian E. Beaman
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Greg M. Walter
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Keyne Monro
- Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Christen K. Mirth
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Carla M. Sgrò
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Craig R. White
- Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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Clark JM, Gibbs AG. Starvation selection reduces and delays larval ecdysone production and signaling. J Exp Biol 2023; 226:jeb246144. [PMID: 37671530 PMCID: PMC10560552 DOI: 10.1242/jeb.246144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 08/22/2023] [Indexed: 09/07/2023]
Abstract
Previous studies have shown that selection for starvation resistance in Drosophila melanogaster results in delayed eclosion and increased adult fat stores. It is assumed that these traits are caused by the starvation selection pressure, but its mechanism is unknown. We found that our starvation-selected (SS) population stores more fat during larval development and has extended larval development and pupal development time. Developmental checkpoints in the third instar associated with ecdysteroid hormone pulses are increasingly delayed. The delay in the late larval period seen in the SS population is indicative of reduced and delayed ecdysone signaling. An enzyme immunoassay for ecdysteroids (with greatest affinity to the metabolically active 20-hydroxyecdysone and the α-ecdysone precursor) confirmed that the SS population had reduced and delayed hormone production compared with that of fed control (FC) flies. Feeding third instar larvae on food supplemented with α-ecdysone partially rescued the developmental delay and reduced subsequent adult starvation resistance. This work suggests that starvation selection causes reduced and delayed production of ecdysteroids in the larval stage and affects the developmental delay phenotype that contributes to subsequent adult fat storage and starvation resistance.
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Affiliation(s)
- Jennifer M. Clark
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV 89154-4004, USA
| | - Allen G. Gibbs
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV 89154-4004, USA
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Murakami K, Palermo J, Stanhope BA, Gibbs AG, Keene AC. A screen for sleep and starvation resistance identifies a wake-promoting role for the auxiliary channel unc79. G3 (BETHESDA, MD.) 2021; 11:6300522. [PMID: 34849820 PMCID: PMC8496288 DOI: 10.1093/g3journal/jkab199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/25/2021] [Indexed: 11/22/2022]
Abstract
The regulation of sleep and metabolism are highly interconnected, and dysregulation of sleep is linked to metabolic diseases that include obesity, diabetes, and heart disease. Furthermore, both acute and long-term changes in diet potently impact sleep duration and quality. To identify novel factors that modulate interactions between sleep and metabolic state, we performed a genetic screen for their roles in regulating sleep duration, starvation resistance, and starvation-dependent modulation of sleep. This screen identified a number of genes with potential roles in regulating sleep, metabolism, or both processes. One such gene encodes the auxiliary ion channel UNC79, which was implicated in both the regulation of sleep and starvation resistance. Genetic knockdown or mutation of unc79 results in flies with increased sleep duration, as well as increased starvation resistance. Previous findings have shown that unc79 is required in pacemaker for 24-hours circadian rhythms. Here, we find that unc79 functions in the mushroom body, but not pacemaker neurons, to regulate sleep duration and starvation resistance. Together, these findings reveal spatially localized separable functions of unc79 in the regulation of circadian behavior, sleep, and metabolic function.
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Affiliation(s)
- Kazuma Murakami
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Justin Palermo
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Bethany A Stanhope
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Allen G Gibbs
- Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
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Bitner K, Rutledge GA, Kezos JN, Mueller LD. The effects of adaptation to urea on feeding rates and growth in Drosophila larvae. Ecol Evol 2021; 11:9516-9529. [PMID: 34306639 PMCID: PMC8293711 DOI: 10.1002/ece3.7770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/22/2021] [Accepted: 05/21/2021] [Indexed: 11/18/2022] Open
Abstract
A collection of forty populations were used to study the phenotypic adaptation of Drosophila melanogaster larvae to urea-laced food. A long-term goal of this research is to map genes responsible for these phenotypes. This mapping requires large numbers of populations. Thus, we studied fifteen populations subjected to direct selection for urea tolerance and five controls. In addition, we studied another twenty populations which had not been exposed to urea but were subjected to stress or demographic selection. In this study, we describe the differentiation in these population for six phenotypes: (1) larval feeding rates, (2) larval viability in urea-laced food, (3) larval development time in urea-laced food, (4) adult starvation times, (5) adult desiccation times, and (6) larval growth rates. No significant differences were observed for desiccation resistance. The demographically/stress-selected populations had longer times to starvation than urea-selected populations. The urea-adapted populations showed elevated survival and reduced development time in urea-laced food relative to the control and nonadapted populations. The urea-adapted populations also showed reduced larval feeding rates relative to controls. We show that there is a strong linear relationship between feeding rates and growth rates at the same larval ages feeding rates were measured. This suggests that feeding rates are correlated with food intake and growth. This relationship between larval feeding rates, food consumption, and efficiency has been postulated to involve important trade-offs that govern larval evolution in stressful environments. Our results support the idea that energy allocation is a central organizing theme in adaptive evolution.
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Affiliation(s)
- Kathreen Bitner
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCAUSA
| | - Grant A. Rutledge
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCAUSA
- USDA HNRCA at Tufts UniversityBostonMAUSA
| | - James N. Kezos
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCAUSA
- Department of Development, Aging, and RegenerationSanford Burnham Prebys Medical Discovery InstituteLa JollaCAUSA
| | - Laurence D. Mueller
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCAUSA
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Collie J, Granela O, Brown EB, Keene AC. Aggression Is Induced by Resource Limitation in the Monarch Caterpillar. iScience 2020; 23:101791. [PMID: 33376972 PMCID: PMC7756136 DOI: 10.1016/j.isci.2020.101791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/27/2020] [Accepted: 11/06/2020] [Indexed: 11/17/2022] Open
Abstract
Food represents a limiting resource for the growth and developmental progression of many animal species. As a consequence, competition over food, space, or other resources can trigger territoriality and aggressive behavior. In the monarch butterfly, Danaus plexippus, caterpillars feed predominantly on milkweed, raising the possibility that access to milkweed is critical for growth and survival. Here, we characterize the role of food availability on aggression in monarch caterpillars and find that monarch caterpillars display stereotyped aggressive lunges that increase during development, peaking during the fourth and fifth instar stages. The number of lunges toward a conspecific caterpillar was significantly increased under conditions of low food availability, suggesting resource defense may trigger aggression. These findings establish monarch caterpillars as a model for investigating interactions between resource availability and aggressive behavior under ecologically relevant conditions and set the stage for future investigations into the neuroethology of aggression in this system.
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Affiliation(s)
- Joseph Collie
- Department of Biological Sciences, and the Program in Neurogenetics, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA
| | - Odelvys Granela
- Department of Biological Sciences, and the Program in Neurogenetics, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA
| | - Elizabeth B. Brown
- Department of Biological Sciences, and the Program in Neurogenetics, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA
- Corresponding author
| | - Alex C. Keene
- Department of Biological Sciences, and the Program in Neurogenetics, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA
- Corresponding author
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