Gregarious behavior of spiny lobsters

1. Cooperative Defense by Non-Kin Related Caribbean Spiny Lobsters Under Attack by Cooperating Predators Kari Lavalli CGS, Division of Natural Science, Boston University William F. Herrnkind Dept. of Biological Science, Florida State University

3. Natural Selection & Evolution

4. Natural Selection is a “Selfish” Process in Many Respects It acts on individuals to maximize their own reproductive output Paradox? We see LOTS of animals living in cohesive social groups, cooperating, and appearing to behave “altruistically”

8. Examples of Arthropod Groups

9. Phalanx of musk ox formed when threatened by wolves (calves and cows on the inside, bulls on the outside rim) The phalanx can also initiate coordinated counterattacks upon attacking wolves

12. Prey Life Cycle

14. Tethering Technique Lavalli & Spanier, 2001. Mar. Freshwat. Res. 52 : 1133-1143.

17. Differences Seen in Predator Behavioral Circuits at 3 Hours Solitary Lobsters Grouped Lobsters

21. Grouping in Panulirus spp. Codenning and emerging en masse is common in some spiny lobster species Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

22. Panulirus argus Lobsters Queue to Move Across Featureless Terrain Most (95%) queues have 5-20 members Few solitary lobsters or small groups (5%) Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

23. Queues Coil into “Rosettes” If Disturbed Antennae directed outward Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

27. Field Studies

28. Field Studies

29. Description of Fish Behaviors APPROACH (APR): Triggerfish swims to between one and two lobster antenna lengths ATTACK (AT): Triggerfish moves to within one lobster antennae length BITE (B): Triggerfish makes contact with the lobster by either smashing the shell with its mouth or by using the mouth to remove antennal tips or eyes SWIM OVER (SO): Triggerfish turns on side while swimming over lobsters at a distance of approximately 2 antennal lengths Lavalli & Herrnkind, 2008. N.Z. Mar. Freshwat. Res. 42 : (in press).

30. Description of Lobster Behaviors ANTENNA POINT (AP): Antennae moved and directed at approaching triggerfish ANTENNA WHIP (AW): Lobster uses one or both antennae to lash at fish LUNGE (L): Lobster rapidly thrusts antennae against fish TAIL FLIP (TF): Rapid abdominal flexion causing backward movement PIROUETTE (P): Animal spins rapidly, pointing antennae towards fish that are approaching in all directions Lavalli & Herrnkind, 2008. N.Z. Mar. Freshwat. Res. 42 : (in press).

31. Pointing by An Individual Lobster

32. Pointing by All Group Members

33. Whipping Behavior

34. Lunging Behavior

37. Field Studies: Results N=10 solitary N=4 groups * ANOVA, p <0.001 Bonferoni post-hoc test, p <0.001

38. Field Studies: Results N=10 solitary N=4 groups * ANOVA, p < 0.001 Tukey test, p < 0.001

40. Mesocosm Studies

41. Mesocosm Studies

42. Mesocosm Studies

44. Hourly Changes in Lobster Group Sizes Observed with No Fish Present % Observed Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

45. Hourly Changes in Lobster Group Size Observed with Fish Present % Observed Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

46. Hourly Changes in Lobster Group Size Observed (20 Lobsters Total) % Observed Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

47. Hourly Changes in Lobster Group Size Observed (10 Lobsters Total) % Observed Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52 : 1113-1124.

50. Solitary Lobsters have Greater per Capita Death Risk, but No Difference for Grouped Lobsters Regardless of # of Fish N=13 N=13 * * ANOVA, p < 0.001 Actual death risk close to risk predicted by dilution

51. Time to Kill Not Affected by # Lobsters or # of Predators N=13 ANOVA, p = 0.55

52. Removal of Stridulating Organ Has an Effect on Attacks/Kills by Naïve Fish N =15 fish per lobster treatment Pearson’s  2 , p < 0.01

57. Questions?

67. Fish Approaches & Passes (Pre-Attack Phase)

68. Triggerfish Hover & Bite Behavior (Attack Phase)

69. Chased and Bitten Triggerfish

70. Fish Involved in the Chases