1. Victoria Morrisey, Kirsten Weagle and Whitney Sipprell
Agonistic behaviors of the house cricket Acheta domesticus displayed in competition for food resources
We worked with crickets and wanted to determine if agonistic behaviors displayed in contests over food items differed between food offered and sexes
Victoria Morrisey, Kirsten Weagle and Whitney Sipprell

2. Resource holding potential
Resources in nature are limited
Mates, food, shelter
Resource holding potential: the fighting success of an individual
Resources for animals ae often finite and there is often competition between conspecifics to sequester food, mates and habitats.
Resource holding potential is the fighting success of an individual. Resource holding potential has been shown to correlate positively with relative body size, aggressive predisposition and prior ownserfip of resources

3. Competition for food
Obtaining food is important for survival and fitness
Willingness to engage in conflict ↑ when food value ↑
Food is an immportat resource to sustain life for all animals. Successful aquistion of food has been shown to increase survival and fitness of an individual.
The value of food is different between items. More nutricious food for a certain animal would be more valuble to obtain. When a food item is more valuble to an individual, it has ben shown that they are more likely to be iwlling to enage in conflict to attempt to secure ownership

4. Agonistic behavior
Group of behavioral adjustments associated with fighting
Threat, aggression
Avoidance and submission
Can cause or prevent bodily harm to an individual
Agonistic behvors are those associated with fighting, and include not just aggressive behaviors but also submissive behaviors D
Agnostiic behaviors can caue of prevent bodily harm to an individual depening on if aggressive or submissive behaviors are displayed. Aggressive behaviors iitaitaed by one individual and th eoppoent chooses if they wil be submissive or agressive

5. Agonistic behavior
Fighting is energetically expensive and risks injury
Motivation to fight
Influenced by the value of the contested resource
Hunger as a factor

6. Acheta domesticus House cricket
Frequent competition likely lead to the evolution of agonistic behaviors
Antennal fencing
Biting, chasing, kicking
Interlocking mandibles
withdrawl from contact
avoidance
← AGRESSIVE
Crickets in fihts often initate conflict with antennal contact. This is thought to be a method to aqquire information about the opponent.
← SUBMISSIVE

7. Past Work
Agonistic displays observed between crickets in the pursuit of resources
Most work done with males
Food is important to both sexes
Females better at obtaining food?
females less likely to fight
Agnostic bhaviors between males are genally more conspicuous
However, food is important to both sexes and it has een shown that feales are better at sequestering food at all life stages

8. Question
Is there a difference between agonistic behaviors displayed by the house cricket Acheta domesticus over food resources?
Between different food resources
Between the different sexes

9. Hypotheses
Different food resources result in different agonistic behaviors
Food items that elicited a more aggressive response are higher values
There would be a difference in the response from females and males
Interactions between female conspecifics would be less aggressive

10. Materials and Methods House Crickets Acheta domesticus lab population
Unlimited food (kibble, apple, potato)
Unlimited water

11. 72 hours prior to testing:
Materials and Methods
72 hours prior to testing:
Isolation in covered plastic cups
Starved
Water provided via moist sponges

12. Testing Same sex pairs of approximately equal sizes Fighting arena
Materials and Methods
Testing
Same sex pairs of approximately equal sizes
Fighting arena
Acclimation for 5 mins with divider
Single food item in the centre
Allowed to interact for 5 minutes

13. Materials and Methods
Testing Arena

14. Scoring Intensity score of 0-4 Highest intensity core reached recorded
Materials and Methods
Scoring
Intensity score of 0-4
Highest intensity core reached recorded

15. Scoring Materials and Methods Adam and Hoy Behavior Description
Intensity score
Still
Immobile for more than 15 s
Withdraw
Moves away from tactile contact
Antennal fencing
Rapidly antennae the opponent’s antennae 1
Kick
Kicks legs at conspecifics 2
Threat posture
Raises forelegs
Mandible flare
Mandibles are extended 3
Chase
Runs after opponent
Lunge
Rushes at conspecific with open mandibles
Bite
Uses mandibles to pinch opponent
Grabble
Crickets interlock mandibles/push and pull opponent 4

16. Mutual avoidance withdrawing
antennal fencing mandible flaring

17. Results
Food source ranks were determined based on the number of highest ranking scores among each food trial.
Low-value= Apple, medium-value= Potato, high-value= Dog food
Statistical analysis: Mann-Whitney U Test
We had to rank our 3 food sources in terms of how valuable they would be to the crickets.
To do this, we observed the responses of the crickets to each food source, and determined which food generated the largest number of the highest aggression scores.
We found that apples generated the fewest number of level 3 scores, dog food generated the highest number, and potatoes ranked in between.
To analyze our data, I used the non-parametric Mann-Whitney U test, since our data was ordinal, meaning that each number represented a specific behaviour, not just a number.

18. Results
Trials conducted using low value-food did not achieve significant results between male and female aggression responses (nm=6, nf=6, U=16.5>Ucrit, p=0.8728).
When comparing male and female aggression using the low-value food item, we found no significant difference because our p-value is greater than 0.05, and our calculated U value is greater than the critical value.
This graph shows the number of crickets that elicited each behaviour when exposed to the low-value food. We found that males elicited the most aggressive behaviours, but our findings were again, not statistically significant.
Figure 1. Male vs. Female Aggression Responses to apple (Low Value Food)

19. Results
Trials conducted using medium-value food did not result in males or females eliciting significantly higher aggression responses than the other (nm=6, nf=4, U=17.5>Ucrit).
When we compared male and female aggression over medium-value food, we found that their aggression levels were not significantly different.
Because our sample size was so small due to complications, R-studio couldn’t actually calculate a p-value for this data. We did however, confirm that it was not significant because the calculated U value exceeds the critical value.
Figure 2. Male vs. Female Aggression Responses to Potato (Medium Value Food)

20. Results
Male and female crickets did not show significantly different levels of aggression when exposed to the high value food source (nm=2, nf=6, U=7>Ucrit).
When comparing aggression levels between males and females using the high-value food source, we found that neither was significantly more aggressive than the other.
This graph shows that females appeared to be more aggressive over the dog food than the males, but the results were not significant.
Figure 4. Male vs. Female Aggression Responses to Dog Kibble (High Value Food)

21. Results
Cumulatively comparing levels of aggression between food sources:
This graph shows the cumulative responses to each food source, ignoring sex differences. We compared the cumulative aggression responses of each food source to the others.
Note the high numbers of crickets eliciting zero aggressive responses.
Figure 5. Collective Aggression Responses to Low, High, and Medium Value Foods.

22. Results Aggression levels between individuals competing over:
 Low- and medium-value food sources did not differ significantly (n1=12, n2=10, p=0.6455).
 High- and medium-value food sources did not differ significantly (n1=10, n2=8, p=0.1211).
 High- and low-value food sources did not differ significantly (n1=12, n2=8, p=0.1141).
When we compared scores between low and medium value food trials, a significant difference was not found. We also did not find any significant differences when comparing high value food with medium value food, and high value food with low value food.

23. Discussion House crickets have a competitive feeding ability
Nosil (2002)
House crickets have a competitive feeding ability
How much do they want the food?

24. Increasing aggression
Food Type and Scores
Increasing aggression
Dog pellets
Potatoes
Apples
Crepsi 1981

25. Could reproduction be affecting their aggression?
Gender and Scores
Males – 1.75
Females – 1.42
Could reproduction be affecting their aggression?
Adam and Hoy 1994

26. Common Agonistic Behaviours
Antennal fencing
Chasing
Biting
Does aggression make you more successful?
Hack 1997

27. Possible Improvements
Raise crickets from birth so that there is a consistent age among them
Use the larger crickets

28. Conclusions
Different food sources did not result in significantly different agonistic behaviours over food.
There was no significant difference between agonistic behaviors between males and females