Photo: Maya Saar (Messor sp.)
Foraging is one of the most fundamental behaviors animals engage in, due to its direct link to the animal’s reproduction and survival. My PhD thesis was completed in Inon Scharf's lab, and it focused on different aspects of foraging behavior in ants and their link to colony fitness. I have studied these aspects in both field and laboratory settings and in 4 co-occurring ant species.
Different foraging strategies facilitates Co-existence in Harvester ants
Here, I demonstrated that harvester ant species differ in their level of behavioral consistency due to different foraging strategies (individual vs. group foragers). I suggested that their distinct foraging behavior enables them to coexist in a shared habitat and share similar resources. I also surveyed & characterized the vegetation occurring in the ants habitat, in Tel-Baruch coastal sand-dunes in Israel, to obtain a solid ecological platform for my following studies.
Relevant publication: Saar M, Subach A, Reato I, Liber T, Pruitt JN, Scharf I. (2018). Consistent differences in foraging behavior in two sympatric harvester ant species may facilitate coexistence. Curr. Zool. 64:653-661. PDF
Genetic diversity contributes to colony fitness in harvester ants
In this study I demonstrated how differences in the level of within-colony genetic diversity that arises from different reproductive strategies (polygynous vs. polyandrous) were later translated to differences in foraging behavior and other aspects of colony performance. The link between high colonial genetic diversity and efficient foraging behavior was tested in bees but rarely in ants, and could explain one benefit of multiple mating in social insects. I also discovered an undescribed harvester ant species by molecular screening of the habitat, which later helped me to develop a research plan to resolve the taxonomic status of its genus (Messor, please see current research).
Relevant publication: Saar M, Eyer PA, Kilon-Kallner T, Hefetz A, Scharf I. (2018). Within-colony genetic diversity differentially affects foraging, nest maintenance, and aggression in two species of harvester ants. Sci. Rep. 8: 13868. PDF
Learning in Foraging context in desert ants
These studies dealt with the contribution of learning to foraging behavior in a desert ant that co-occur with the harvester ants from my previous work. We used this species because many congeneric species has demonstrated excellent navigation skills in past studies. However, unlike many of their desert-dwelling congeneric species, Cataglyphis niger dwells in human populated coastal areas in Israel, and need to navigate through much more complex environments (that usually provides obstacles such as debris, rocks, dense vegetation, etc.) while foraging. Therefore, learning the complexity of their habitat should increase colony fitness. I demonstrated that ants shortened their time in solving mazes with experience, and that they did so better for a preferred food type. I also demonstrated the rate at which the ants seemed to 'forget' how to solve the maze, although they were experienced.
1. Saar M, Hershkoviz D, Amano O, Bega D, Subach A, Scharf I (2020). The effect of food preference, landmarks, and maze shift on maze-solving time in desert ants. Behaviour. 157:629-665. PDF
2. Bega D, Samocha Y, Yitzchak N, Saar M, Subach A, Scharf I. (2020). Non-spatial information on the presence of food elevates search intensity in ant workers, leading to faster maze solving in a process parallel to spatial learning. PLoS One. 15: e0229709. PDF
3. Bega D, Samocha Y, Yitzchak N, Saar M, Subach A, Scharf I. (2019). The effect of habitat complexity on maze-solving time in a desert ant. Behav. Processes. 166: e103893. PDF
4. Saar M, Gilad T, Kilon-Kallner T, Rosenfeld A, Subach A, Scharf I. (2017). The interplay between maze complexity, colony size, learning and memory in ants while solving a maze: a test at the colony level. PLoS One.12: e0183753. PDF
Population structure of the desert ant
My MSc study was carried out in Prof. Abraham Hefetz's lab. It was then that I began studying the basic biology of desert ants which were one my focal research animals later in my PhD. Here I examined C. niger's population structure using combined chemical, molecular, and behavioral methods.
Relevant publication: Saar M*, Leniaud L*, Aron S, Hefetz A. (2014). At the brink of supercoloniality: genetic, behavioral, and chemical assessments of population structure of the desert ant Cataglyphis niger. Front. Ecol. Evol. 2: 13. PDF
* equal contributions