I’m an EMBO Post-Doctoral Fellow
at Rutgers University - Camden
I explore the processes and mechanisms
underlying social behavior in ants
from the molecular to the organismal and
societal levels.
My Research
My long-term research goal is to understand what mechanisms determine behavior and how individual behaviors affect evolutionary processes. Learn more about my ongoing research projects below.
Epigenetic regulation on Social life
Like human societies, ant colonies rely on the principle of division of labor. In ants, this consists in the development of phenotypically distinct individuals from the same genome. Thus, ants are a powerful model system to study epigenetic regulation from the molecular to the organismal and societal levels. Our previous work suggests that epigenetic signals, including noncoding RNAs, contribute to the distinct phenotypes of workers and queens but the molecular mechanisms remain unknown. One possibility is that workers influence the epigenetic state of larvae at critical windows during development. A natural candidate for this inter-individual epigenetic control, which has been a recent focus of studies in social insects, are mobile RNAs that are transmitted to the larvae by the exchange of “social” fluids. Generally, there is growing evidence for epigenetic regulation by horizontally and vertically transmitted noncoding RNAs in all kingdoms of life.
Neuronal Plasticity in Adult Ant Brains During Caste Transition and its Effect on Learning and
Memory
Neural plasticity is a key feature in adapting to changing environments; yet, how genetic and epigenetic regulation is involved in this process is poorly understood. Harpegnathos ants offer a unique model system to study the molecular regulation of neurodegeneration and, possibly, regeneration in a natural setting. The reproductive biology in this species is unusual: if the residing queen dies, workers can replace her by undergoing a behavioral switch to achieve queen-like status (gamergates). I exploit this unique system to study the molecular mechanisms of neural plasticity in vivo and their effects on learning and memory.
Diversity of Social and Population Structures in the Desert Ant Cataglyphis
In social insects, due to considerable polyphenism as well as a high level of hybridization, the delimitation of species can be challenging. The genus Cataglyphis presents a high level of diversification, making it an excellent model with which to study evolutionary paths. Israel appears to be a “hot spot” for recent speciation in this genus. Although previous studies have described multiple species of Cataglyphis in Israel, we held a phylogenetic study that has questioned the existence of some of these historically described species. As well as identified a new species C. israelensis. The species complex includes the previously known: C. niger, C. savigyi, and C. drusus that are distinguishable by their mitochondrial DNA (and therefore named mitotypes) but not by their nuclear DNA. Using a multi-method approach (genetics, chemistry, and behavior), we show that these mitotypes also differ in their social structures and are readily distinguishable by their cuticular hydrocarbons profiles. While most populations of the different mitotypes are allopatric, at our study site they are sympatric but nonetheless maintain the observed differences between them. This raises the evolutionary question: Are these incipient species that have diverged with gene flow, or is this a case of social and chemical polymorphism that is maintained within a single species? Unveiling the interplay between social polyphenism and species segregation is at the core of evolutionary biology.
Multiple-Queen Colony Behavior and Demography
Ants show a remarkable diversity in the social organization from the ancestral colony that was presumably composed of a single-queen, singly-inseminated and her daughter workers to more derived states of multiply- inseminated queens and multiple-queen colonies. Multiple-queen colonies pose two problems: queens are predicted to compete for monopoly in reproduction; workers are predicted to favor their own matriline in rearing gynes. Using a QR-coding system that allows us to indicate the proximity between queens and workers, along with polymorphic DNA microsatellite markers indicating the matriline and patriline of each worker in the nest, we demonstrate the complex social interactions in multi-queen nests of Cataglyphis niger. Our data suggest that all queens in the nest are functioning as queens, fertile, and attended similarly by related and unrelated workers. Associations between individuals in the nest are not attributed to genetic relatedness, and most of the individuals are unrelated. This portrays the complex dynamics of a multi-queen colony that is a part of a supercolony, where individuals associate according to the colony’s necessities.
Bacterial Community Compositions in Hedgehogs and their Ectoparasites
Different ecological factors relating to vertebrate host, arthropod ectoparasites (vectors), and environmental variables are expected to have major effects on bacterial community composition. The hedgehog- tick- flea- bacteria model system is convenient to test this question because it is a multi-species system (two species of hosts and two species of vectors), known to harbor bacterial species of zoonotic importance. Preliminary field-collected data showed that ectoparasites (ticks and fleas) infestation differ between hedgehogs’ species and sex. Bacterial communities in the ticks, fleas, and hedgehog’s blood were dominated by mainly one or two bacterial symbionts. Prevalence of the main tick’s bacterial symbiont, Rickettsia, was shown to be different between ticks collected from different hedgehog species, sex and age. In addition, the bacterial composition of hedgehog blood was different between the two hedgehog species. This difference may account for the presence of fleas on the hedgehogs. Overall, results suggest that hedgehog species and sex are the main factors in determining flea and tick densities and the bacterial community composition in hosts and vectors.
Sexual Selection Signals in the East-Mediterranean Barn Swallow
The level of expression of sexually selected traits is generally determined by genes, environment, and their interaction. In species that use multiple sexual signals which may be costly to produce, investing in the expression of one sexual signal may limit the expression of the other, favoring the evolution of a strategy for resource allocation among signals. As a result, even when the expression of sexual signals is condition-dependent, the relative level of expression of each signal may be heritable. We tested this hypothesis in the East-Mediterranean barn swallow (Hirundo rustica transitiva), in which males have been shown to express two uncorrelated sexual signals: red-brown ventral coloration, and long tail streamers. We showed that variation in both signals may partially be explained by age, as well as by paternal origin (genetic father-son regressions), but that the strongest similarity between fathers and sons is the relative allocation towards one trait or the other (relative expression index), rather than the expression of the traits themselves. These results suggest that the expression of one signal is not independent of the other, and that genetic strategies for resource allocation among sexual signals may be selected for during the evolution of multiple sexual signals.
In this study, I set up a ‘common garden’ experiment to check the effects of the environment on the expression of sexual signals. From my results, we saw that the sexual signals are condition dependent.
Males show indiscriminate mating behavior
Sexual selection studies usually report on the female selection, as she will determine the next generation. It is thus unclear as to what extent do males engage in promoting divergence or gene flow.
The barn swallow (hirundo rustica) species complex provides a model for the study of sexual selection and speciation. In Israel, the two sub-species are genetically very similar, with genetic evidence of gene flow after divergence, but present differences in sexual signals. As such, we were interested in whether sub-species recognition occurs and, if so, promotes pre-mating isolation between the two sub-species. I tested the response of resident breeding pairs to taxidermically prepared models of transitiva and rustica males, sand martin (another same-sized member of the hirundindae family), and house sparrows, a known nest competitor. While females did not show clear responses to the models, males displayed clear sexual behavior that included singing and repeated mounting attempts toward both sub-species of h. rustica and the sand martin, but not toward the sparrow (that was occasionally mobbed). These results suggest that male swallows would mate indiscriminately with almost any receptive swallow and their behavior may promote gene flow rather than population divergence.
A similar species complex is the Cataglyphis niger complex, where different mitotypes present differences in recognition ques. I checked whether males would mate with the other mitotypes by analyzing the sperm content within the spermatheca of queens. The genetic analysis revealed that males mate indiscriminately thus promoting gene-flow between mitotypes.
Reiner Brodetzki, T., Lotem, A., Safran, R. J., & Hauber, M. E. (2021). Lack of subspecies-recognition in breeding Barn Swallows (Hirundo rustica transitiva). Behavioural Processes
Reiner Brodetzki T., Brodetzki G., Feinerman O., & Hefetz A. (2019) Worker demography and behavior of a supercolonial ant colony: the case of the desert ant Cataglyphis niger. Ethology
Reiner Brodetzki T., Inbar, S., Cohen, P., Aron, S., Privman, E., & Hefetz, A. (2019). The Interplay between Incipient Species and Social Polymorphism in the Desert Ant Cataglyphis. Scientific Reports 9(1), 9495
Reiner Brodetzki T., Hefetz A. (2018) Determining social and population structures requires multiple approaches: A case study of the desert ant Cataglyphis israelensis. Ecol Evol., 00:1–10.
Eyer P. A., Seltzer R., Reiner-Brodetzki T., & Hefetz A. (2017) An integrative approach to untangling species delimitation in the Cataglyphis bicolor desert ant complex in Israel. Molecular Phylogenetics and Evolution, 115, 128-139.
Vortman Y, Safran RJ, Reiner Brodetzki T, Dor R, Lotem A (2015) Expression of Multiple Sexual Signals by Fathers and Sons in the East-Mediterranean Barn Swallow: Are Advertising Strategies Heritable? PLoS ONE 10(2): e0118054
Awards & Fellowships
2020- current
EMBO long-term postdoctoral fellowship
2018
Pick-Melamed travel grant
2016
1. Minister of science travel fund
2. Fishelson travel fellowship for zoology students
3. International Society for Behavioral Ecology travel fellowship
2015
Constantiner Institute for Molecular Genetics travel fellowship
2014
1. David Furth travel fellowship for entomology students
2. Tel-Aviv University Global Research & Training Fellowship in Medical and Life Sciences Fund and Naomi Kadar Foundation
2012-2013
Robert H. Smith fellowship for excellence
Outreach & Volunteer work
ScienceAbroad Philadelphia
Branch Manager
ScienceAbroad is an Israel-based nonprofit organization that harnesses the power of senior Israeli scientists living abroad. Through its wide-reaching professional and social network, ScienceAbroad inspires connections with local communities, international scientists, and Israel.
Nature Campus Instructor at Tel-Aviv Zoological garden
Nature Campus activities foster respect for the natural world, instill knowledge of ecological and evolutionary processes, and provide insights into the complexities of nature.
Elementry school outreach
Raising STEM awareness in public school children through the diverse world of ants.
Children TV show 'Shoshter & Shoshter'
About
As a child growing up I was always intrigued by the questions of how and why do organisms behave the way they do. When I grew up I interpreted these questions to a fascination with biology, specifically in behavioral ecology. During the past years, I explored several model systems trying to answer different behavioral and evolutionary questions. I did this by applying a wide range of methods from behavioral analysis, genetics, epigenetics, and chemical approaches.
As a mother, I am keen on sharing my passion for science with children and especially young women to show them how passion can become a career.
