• Raghavendra Gadagkar

      Articles written in Resonance – Journal of Science Education

    • The Honeybee Dance-Language Controversy Robot Bee Comes to the Rescue

      Raghavendra Gadagkar

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    • Africans in the Americas; A Problem?

      Raghavendra Gadagkar

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    • The Making of a Scientist

      Raghavendra Gadagkar

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    • Evidence for Bird Mafia!

      Raghavendra Gadagkar Milind Kolatkar

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    • Konrad Lorenz

      Raghavendra Gadagkar

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    • What is Life? – Reconsidered

      Raghavendra Gadagkar

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    • The True Origin of Agriculture: Credit Goes to the Ants

      Raghavendra Gadagkar

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    • The Origin and Resolution of Conflicts in Animal Societies - The Case of the Bees and the Birds

      Raghavendra Gadagkar

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    • Genomic Imprinting - Some Interesting Implications for the Evolution of Social Behaviour

      Raghavendra Gadagkar

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    • Bill Hamilton - The Greatest Darwinian Since Darwin

      Raghavendra Gadagkar

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    • Donald Griffin Strove to give Animals their Due

      Raghavendra Gadagkar

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    • The Logic of Animal Conflict

      Raghavendra Gadagkar

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    • “Nothing in Biology Makes Sense Except in the Light of Evolution”

      Raghavendra Gadagkar

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    • Where Humans are Animals and Animals are Human

      Raghavendra Gadagkar

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    • What Do Ethologists Wish to Know?

      Raghavendra Gadagkar

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    • How to Design Experiments in Animal Behaviour 1. How Wasps Find Their Nests

      Raghavendra Gadagkar

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      In this series of articles, I will introduce the reader to the scienceof ethology, somewhat indirectly by describing simpleexperiments, both old and new, designed to understand howand why animals behave the way they do. My emphasis willbe on the design of the experiments and my goal will be tomotivate readers not only to think about the design but alsoto come up with alternatives and improvements. Motivatedreaders can indeed replicate some of these experiments evenif they end up replacing the study animal or the behaviours ofinterest with their own favourite choices. In the first part ofthe series, I describe how Niko Tinbergen – Nobel Laureateand one of the founding fathers of ethology (the science of animalbehaviour) – designed remarkably simple experimentsto successfully understand how digger wasps find their ownnests in a complex habitat also consisting nests built by otherwasps.

    • How to Design Experiments in Animal Behaviour: 2. Do Bees Have Colour Vision?

      Raghavendra Gadagkar

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      In the second article in the series, I will describe how theyoung Karl von Frisch, later to become another founding fatherof ethology and Nobel Laureate, defied established authorityto design simple yet logically clever experiments toshow that honey bees indeed have colour vision. His experimentsforever changed our view of animals and also the wayexperiments in animal behaviour are designed. It might interestreaders to know that Karl von Frisch’s experimentsdescribed in this part inspired Tinbergen’s experiments describedin the previous article in this series.

    • How to Design Experiments in Animal Behaviour 3. How Do Ants Find the Shortest Path?

      Raghavendra Gadagkar

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      In this article, I will describe how a simple, curiosity-basedexperiment to understand how ants are smart enough to choosethe shortest path led the exploration of self-organization andswarm-intelligence and resulted in major applications in computerscience and optimization algorithms. The focus willbe on curiosity, simplicity, interdisciplinarity, and being unmindfulof immediate applications.

    • How to Design Experiments in Animal Behaviour: 4. How Do Bees Estimate the Distance Flown?

      Raghavendra Gadagkar

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      This article describes simple experiments that showthat honeybees estimate the distance they have flown, by means of ‘opticflow’, i.e., the extent of image motion experienced by theireyes. The estimated distance is then communicated to thebees at home through the tempo of their dance (number ofdance circuits in 15 s) or the duration of the waggle phase ineach circuit. The experiments also provide strong evidenceagainst the previously held view that distance is estimatedby the amount of energy consumed during the flight. Theseexperiments illustrate how cutting-edge research is possiblewith little or no facilities, equipment or money, by asking theright questions, optimizing the design of the experiments andregarding previously fashionable theories with an appropriatedegree of scepticism.

    • Democratizing Science and Redefining Education

      Raghavendra Gadagkar

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    • Series Article

      Raghavendra Gadagkar

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      In this article, I will describe experiments designed to understand how ants estimate the distance they have walked. They rival in their simplicity, the experiments described in my previous article, designed to understand how bees estimate the distance flown. Although ants can also use optic flow to estimate distance, in the absence of optic flow cues and of pheromone/chemical trails, as may sometimes be the case in the desert ants, \emph{Cataglyphis}, ants estimate the distance walked, not by the energy expended but, believe it or not, by `counting' (or integrating) the number of steps they have taken. This was proved by showing that ants on stilts (elongated legs) overshot the required distance to return home while ants on stumps (shortened legs) undershot the required distance.

    • How to Design Experiments in Animal Behaviour: 6. Why are Male Wasps Lazy?

      Raghavendra Gadagkar

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      In this article, we move from sensory physiology to psychologyand consider the proverbially lazy drone. I will describehow some simple experiments permitted us to understandwhy males in the Indian paper wasp Ropalidia marginata dono work in the colony even during the time they live in it. Takingthe behaviour of feeding larvae as an example of work,we show that male wasps normally do not feed larvae, not becausethey are incapable of doing so, but because they do nothave access to enough food and also because female wasps areso much better at this job. As a confirmation of this conclusion,we could cure the males of their laziness, i.e., get themto feed the larvae by providing them with excess food andleaving them in the presence of hungry larvae, without thepresence of females.

    • How to Design Experiments in Animal Behaviour: 7. How Do Wasps Decide Who Would Be the Queen? Part 1

      Raghavendra Gadagkar

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      In this, and the next few articles, we will continue to explorethe social biology of the primitively eusocial wasp Ropalidiamarginata through simple experiments. Since eachwasp colonyhas a single fertile queen and several sterile workers, andsince all or most wasps are capable of taking on both roles,the wasps have to decide who will be the queen and who willbe the worker/s. Such a decision has to be made both whennew colonies are being initiated as well as when an old queenin a mature colony has to be replaced by a new one. Here, Iwill describe a simple laboratory experiment that reveals thatin the context of new nest initiation, wasps decide who will bethe queen by fighting—the winner becomes the queen and theloser/s become the worker/s. The same experiment, in additionto revealing the proximate mechanism of the division ofreproductive and non-reproductive labour, also throws lighton the advantages of such division of labour.

    • How to Design Experiments in Animal Behaviour: 8. How Do Wasps Decide Who Would Be the Queen? Part 2

      Raghavendra Gadagkar

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      Continuing to explore the fascinating world of the Indian paperwasp Ropalidia marginata, in this article, we will ask howwasps choose their queens in another context. In the previousarticle in this series, we saw how a simple experiment revealedthat wasps fight, i.e., indulge in dominance-subordinateinteractions, and the winner becomes the queen and theloser becomes the worker. This was in the context of newnest foundation. But contextmatters. When the same waspsonce again have to decide who will be their next queenif the first one dies or is experimentally removed, the samerules do not hold. The wasps in a mature colony continueto show dominance-subordinate interactions and can even bearranged in a dominance hierarchy, but the dominance ranksof the wasps do not predict who their next queen will be.How they choose their next queen in this context continuesto be an enduring mystery. In this article, I will describe foursimple experiments that have helped us come close to nailingthe culprit, although I must confess that we have not yetfound the smoking gun—the chase is on, and we are hot onthe trail—please join in!

    • How to Design Experiments in Animal Behaviour∗ 9. Why Do Wasps Fight? Part 1

      Raghavendra Gadagkar

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      Continuing to explore the intriguing world of the Indian paperwasp Ropalidia marginata, here we will focus on their fighting behaviour. When wasps fight, there is, as expected, a winner and a loser. The winner is said to have shown dominance behaviour, and the loser is said to have shown subordinate behaviour. What is the function of such dominance subordinate behaviour? We saw in the 7th article in this series [1] that in the context of founding new nests, wasps fight to decide who would be the queen and who would be the worker. We then saw in the 8th article in this series [2] thatwhen wasps have to decide who would be their next queenin a mature colony, they do not decide by fighting, although they fight for other reasons. We will see in this article that workers continue to show dominance-subordinate behaviour in mature colonies. What is the function of this aggression displayed by the workers? In this article, I will describe two simple experiments that help us answer this question, and show that the function of wasp aggression can be quite different in different contexts.

    • How to Design Experiments in Animal Behaviour 10. Why Do Wasps Fight? Part 2

      Raghavendra Gadagkar

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      Continuing to explore the intriguing world of the Indian paperwasp Ropalidia marginata for one last time, here we willfocus on the function of fighting behaviour in two additionalcontexts (i) the hyper-aggression of the potential queen duringqueen succession and (ii) during encounters with nonnestmatewasps. We will see again that the function of fightingis different in different contexts. We have already seentwo different functions of fighting in two different contexts—to decide who will be the queen and who will be the workerin the context of founding new nests, and to regulate foragingin mature colonies by conveying colony hunger levels toforagers. Here we will see that the function of the potentialqueen’s hyper-aggression is to boost her own ovarian developmentand the function of aggression towards non-nestmates isto keep them away, and if necessary, to kill! As before, ourprimary focus will be on how to design simple experimentsthat will help answer a direct question, while minimising theneed for expensive equipment or other facilities.

    • Half a Century of Worship at “Tata’s Temple of Science”

      Raghavendra Gadagkar

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    • How to Design Experiments in Animal Behaviour: 12. Male Frogs Sing for Sex but Why Don’t They Do Their Best?

      Raghavendra Gadagkar

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      Charles Darwin proposed a separate theory of sexual selec-tion, as distinct from his theory of natural selection, to ac-count for adaptations that confer success in finding a mate, which may sometimes be quite the opposite of what is best for survival. Darwin’s proposal that females have a sense of beauty and choose mating partners that appear beautiful to them was met with much scepticism. But today we have a rather detailed understanding of what animals find beauti-ful and why. In this article, I will describe a few very sim-ple experiments performed by Michael J. Ryan, in collabora-tion with A. Stanley Rand, herpetologist extraordinaire and Merlin D Tuttle of the Bat Conservation International fame, that laid the foundation for our current understanding of the meaning and evolution of beauty. Studying the t´ungara frog on Barro Colorado Island, a research station of the Smithso-nian Tropical Research Institute in Panama, they showed that (1) male t´ungara frogs can produce both simple calls, consist-ing of just a whine, or complex calls in which one or more chucks are added to the whine, (2) female t´ungara frogs have a decided preference to mate with males giving complex calls,(3) males are nevertheless reluctant to add chucks to their calls and generally do so only when they hear other males calling, and (4) the local predatory fringe-lipped bat also has a decided preference to eat males giving complex calls. Male t´ungara frogs thus face a trade-off between sex and survival. These experiments not only answered the question of why males don’t do their best when it comes to singing, but they also set the stage for many more sophisticated investigations that have led to an understanding of how and why natural selection has favoured this particular sexual aesthetic in the frogs and this particular culinary aesthetic in the bats.

    • How to Design Experiments in Animal Behaviour: 13. Harmless Snakes Mimic Venomous Snakes to Avoid Predation, But Why Don’t They Do Their Best?

      Raghavendra Gadagkar

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      There are many examples of perfectly palatable animals re-sembling related unpalatable species and, thereby, avoiding attack by predators who have learnt or evolved to avoid the unpalatable species. To facilitate recognition by predators, unpalatable species often have warning colourations, which is what is mimicked by the palatable species. This form of mimicry is known as Batesian mimicry. While there are many well-documented examples of Batesian mimicry among butterflies and other arthropods, there are somewhat fewer examples amongst vertebrates, and even these examples are of-ten debated. The coral snake mimicry system in North America, where non-venomous kingsnakes and milksnakes mimic venomous coral snakes, is one of the best-studied vertebrate examples of Batesian mimicry. However, it has also been debated for over a century. In this article, I will describe three experiments using plasticine replicas of the mimics designed to understand the effectiveness of their mimicry. These field experiments were performed in the natural habitats of the mimics, the models and their predators, by David W. Pfennig and his students and collaborators, in the states of Florida, North Carolina, South Carolina, and Arizona in the USA. The simple, clever, and low-cost experiments have significantly strengthened the hypothesis of Batesian mimicry in this system. They have also provided an unexpected new understanding of how mimics might evolve from cryptic ancestors through a process of gradual natural selection.

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