Moshe Zaguri, a Ph.D. candidate at The Hebrew University of Jerusalem, discusses his paper “Odours of non-predatory species help prey moderate their risk assessment”, the importance of this work, as well as his research interests.

What is the background behind your paper?

Prey animals must balance the need to eat while not being eaten. They do so by constantly updating their risk assessment and consequent defensive reactions, using perceived information.

Thus, prey should not overreact to any possible sign of danger. The information-theoretic approach suggests that animals should use as much sensory information available to increase the accuracy and reliability of their risk estimation. However, our conceptualization is heavily biased towards information that infers danger. 

What’s your paper about?

In this paper, we tested whether prey animals use safety cues (i.e., information that implies safety conditions) in addition to risk cues to complement their risk estimation. Imagine walking in a dark alley when suddenly a large man appears.  A gun in the man’s hand will obviously enhance our fear, but noticing the police badge on the man’s belt may completely relieve our fear.  Similarly, we hypothesized that prey, when approaching an area that may harbour risks, should use non-predatory species cues to moderate their fear. The armed man in our experiment were soil mounds that are perceived as a potential threat by the desert isopods because they are characteristically found outside the burrows of their main predator, the Golden Israeli scorpion. Since several other organisms in this habitat excavate the soil and create such mounds, we used the odours of those non-predatory species as the ‘police badge’ that might inform the isopods that the mounds do not imply risk but were rather created by non-threatening species.

How is your paper new or different from other work in this area?

Most previous work on how prey perceive the risk of predation focus solely on cues that infer risk. We complemented this view by empirically showing that safety cues from non-predatory species play an important role in the prey risk assessment as well.  Our study is also unique in its execution in field conditions, and in comparing isopods of the same family who live in the same burrow, which allowed us to minimize the variation caused by genetic and past experience differences.

About the research

Why is it important?

The results of our research demonstrate that prey use odours of non-predatory species to moderate risk estimation. Our findings open a whole new avenue of research by suggesting the many sources of information that are not directly associated with elevated risks of predation may be used to improve the accuracy and reliability of the prey risk estimation. This notion reveals a new type of non-trophic interaction between species and highlights the need to conserve the information network of a food-web. Extinction of certain information nodes may trickle through the food-web and negatively affect other prey species that may pay the costs of overestimating risks.

What does your work contribute to the field?

Studies of predator-prey interactions need to consider this potentially valuable source of information. Our findings indicate that the routine use of non-predatory species cues (usually odours or vocalization) as control treatments to predator cues may not be adequate since these cues may provide meaningful information. In this regard, the results and effect sizes of previous studies who used this design should be treated with a grain of salt.

What would you like to do next?

In our current research, we used behavioral responses as an indicator of the level of the estimated risk. I want to continue this path of research by testing prey’s anti-predatory responses (i.e., physiology, morphology, and more foraging related behavioral responses) to reveal how moderation of risk estimation by safety cues may affect prey’s fitness.

About the Author

What’s your current position?

I am a Ph.D. student in the Risk Management Ecology lab of Prof. Dror Hawlena, at The Hebrew University of Jerusalem. I am about to complete my dissertation and continue publishing the results of my Ph.D. and additional projects.  I am currently searching for a postdoc position that will allow me to advance our understanding of predator-prey interactions in an agricultural context.  

What project/article are you most proud of?

My main research, which is yet unpublished, explores what inducible defences isopods deploy in response to the risk of scorpion predation and how those changes alter their trophic function and, consequently, the nutrient dynamics of a desert ecosystem.

You can read the paper here and the plain language summary here.