Phragmosis

A type of defensive behaviour in which an animal uses its body parts to block its nest entrance.
In this, Phragmosis mainly invoved in insects are detailed

1. LIVING DOOR Phragmosis N.Mugundhan Sr.M.Sc , Agricultural Entomology Id No : PALB 8139 Welcome SEMINAR -1 Department of Entomology UAS, GKVK Bengaluru-65

2. Insect Defence

3. Amphibians Enemies of Insects Other arthropods Mammals Birds Great Humans

4. All insects are potential prey or host to many kinds of Predators or Parasitoids”

5. “To make or keep safe from danger, attack or harm “ Sigmund Freud (1894) SAFETY

6. CONTENT Phragmosis Examples of Phragmosis Ecological Specialization - Ants Colony stabilization - Termites Head plug Defense - Aphids Conclusion Phragmotic and Trapping - Pachyteles

7. Phragmosis  is any method by which an animal defends itself in its burrow, by using its own body as a barrier. What is Phragmosis ? W.M. Wheeler (1927 )

8. Importance? Potential predators Adverse climatic factors To maintain constant conditions inside the chamber Crypsis Moulting and metamorphosis

9. PACHYTELES APHIDS ANTS TERMITES PHRAGMOSIS SPIDERS

10. G enus Cyclocosmia (Arachnida : Araneae : Ctenizidae ) Habitat?

11. Phragmotic position

12. Phragmotic and Trapping organ Discotelic Paussini – Carabidae GIULIO, A. AND TAGLIANTI, V., 1970

13. Habitat Humid sandy banks of streams and ditches with scattered low vegetation . Ecotone

14. M ainly with fruit flies , but also accepted other insects (aphids, flies, termites, ants, beetles and moths and their immatures Methods Species No of Larva Instar Pachyteles vignai 20 I & II P. digiulioi 15 II & III Prey GIULIO, A. AND TAGLIANTI, V., 1970

15. Hunting and feeding behaviours GIULIO, A. AND TAGLIANTI, V., 1970

16. Selection of size of the prey The diameter of the entrance is surely the definitive filter limiting the maximum size of a prey GIULIO, A. AND TAGLIANTI, V., 1970

17. Symphily True guests in ant colony Tended by the ants Produce secretion which attracts ants

18. Head-plug defense in a gall aphid Gall-forming aphid Astegopteryx sp. B enjamin tree- Styrax benzoides KUROSU et.al ., 2006

19. Soldier Plug the ostiole of the subgall Pierce enemies like moth larvae Push garbage out of the gall Disturbed, soldiers rush out with abdomen upcurved Entrance- guarding and rushing-out tactics One or few ostioles open,aphid can go out

20. KUROSU et.al ., 2006

21. Head-plug defense Total Galls 15 Total Ostioles 173 Completely Plugged 157 (90.8%) Wax-coated globules of honeydew Cast-off skins Shriveled sexuals Live males Live (but possibly aged) apterous adults KUROSU et.al ., 2006

22. Colony composition for 10 subgalls Contained - 120–227 soldiers (mean 178.5 ) KUROSU et.al ., 2006

23. Experiment No of Subgalls examined Soldiers came out Remained outside 1 10 140 54 (38.6 %) 2 10 89 47 (52.8 % ) Case Numbers Total Enounters b/w soldier and guarding soldier 75 Soldiers entered without being blocked by GS 22 Soldiers blocked by GS 53 Soldiers managed to enter subgall 20 Soldiers failed to enter 32 Moribunded 1 Interaction between outside and inside soldiers KUROSU et.al ., 2006

24. Interaction between guarding soldiers and sexuals F irst-instar sexuals - 12 introduced onto a subgall T wo males came to the ostiole T hird male joined them. Many sexuals - Intruding into subgalls guarded by soldiers Field observations Lab observations KUROSU et.al ., 2006

25. Interaction between guarding soldiers and other insects Four soldiers attacked the larva. After depositing them in alcohol we confirmed , three soldiers were piercing the larva with their stylets. KUROSU et.al ., 2006

26. Why do soldiers prevent colonymates and sexuals from coming in? KUROSU et.al ., 2006

27. Phragmosis acts in a stabilization and as ecological specialization?

28. The morphological specialization seen within the workforce of some insect societies is the most striking example of this phenomenon. Individual specialization within a larger group context is of central importance to the organization of animal societies. (Oster and Wilson, 1978 ) Social Insects Polymorphic worker in Solenopsis invicta social insects with clear morphological adaptations to different roles.

29. Advantage ? Ecological specialization and the evolution of a specialized caste in Cephalotes ants POWELL, S., 2008

30. Morphological Specialization No soldier (ancestral) Simple domed head Soldiers - Elaborate and complete head-disc Cephalotes pusillus Cephalotes depressus Cephalotes atratus Cephalotes persimilis Incomplete head-disc (retains domed head) Specialized use of cavities with entrances close to the area of one ant head has driven the evolution of a morphologically and behaviourally specialized soldier in Cephalotes ants. POWELL, S., 2008

31. Could evolutionary shifts in ecology explain soldier evolution? ( Irschick et al ., 2005)

32. FIELD SITE AND FOCAL SPECIES Methods Cerrado reserve of Clube Caçae Pesca Itororó , Ublerlândia , Brazil . 4 – different Character States POWELL, S., 2008

33. NEST DEFENCE AND BEHAVIOURAL SPECIALIZATION OF SOLDIERS Azteca ants To elicit defensive response (Forceps – 45s) Attacks on the Azteca worker & number and caste of individuals that blocked the nest entrance 10 trails – 9 nest tested for each species Soldiers in foraging (3 species) Baits - 1 m (Caste of the ant that discovered the bait )

34. NESTING ECOLOGY Abandoned cavities of wood-boring insects Some cavities ( ≤ 5 ) Newly inhabited (Workers removing frass from the original occupant) No evidence : Excavate the hard wood of the cavities they occupied (Small plier like mandibles) POWELL, S., 2008

35. ECOLOGICAL SPECIALIZATION Outlier boxplots of nest entrance area Outlier boxplots of the standardized nest entrance area (entrance area/max. head area ) POWELL, S., 2008

36. C. atratus C. pusillus C. depressus C. persimilis Soldier morphology No soldier Domed head Incomplete head-disc Complete head-disc Defensive strategy Attack and block (all trials) Attack and block (all trials) Block only (all trials) Block only (all trials) Caste of blockers Workers only Soldiers and workers Soldiers and workers Soldiers only Mean number of ants blocking small entrances (3 nests per species, 10 trials per nest) 2·0 (SD ± 0·0; Pred. = 1·0) 1·7 (SD ± 0·5; Pred. = 0·7) 1·0 (SD ± 0·0; Pred. = 0·6) 1·0 (SD ± 0·0; Pred. = 0·9) 2·4 (SD ± 0·5; Pred. = 1·3) 2·3 (SD ± 0·5; Pred. = 1·0) 1·0 (SD ± 0·0; Pred. = 0·8) 1·0 (SD ± 0·0; Pred. = 1·0) 2·5 (SD ± 0·5; Pred. = 1·4) 2·4 (SD ± 0·5; Pred. = 1·1) 1·0 (SD ± 0·0; Pred. = 0·6) 1·0 (SD ± 0·0; Pred. = 1·0) Mean number of ants blocking mean entrances (3 nests per species, 10 trials per nest) 4·6 (SD ± 0·8; Pred. = 3·4) 3·8 (SD ± 0·8; Pred. = 2·4) 1·0 (SD ± 0·0; Pred. = 1·2) 1·1 (SD ± 0·3; Pred. = 1·3) 5·5 (SD ± 0·5; Pred. = 3·8) 3·9 (SD ± 1·0; Pred. = 2·6) 2·2 (SD ± 0·4; Pred. = 1·3) 1·3 (SD ± 0·5; Pred. = 1·3) 8·8 (SD ± 0·6; Pred. = 5·5) 4·2 (SD ± 0·8; Pred. = 2·6) 2·4 (SD ± 0·5; Pred. = 1·2) 1·3 (SD ± 0·5; Pred. = 1·3) Mean number of ants blocking large entrances (3 nests per species, 10 trials per nest) 8·8 (SD ± 0·6; Pred. = 5·5) 6·6 (SD ± 0·9; Pred. = 5·6) 2·0 (SD ± 0·0; Pred. = 1·8) 3·2 (SD ± 0·4; Pred. = 2·1) 13·6 (SD ± 1·2; Pred. = 8·3) 8·2 (SD ± 1·3; Pred. = 6·8) 3·2 (SD ± 0·4; Pred. = 2·2) 3·4 (SD ± 0·5; Pred. = 2·2) 13·7 (SD ± 1·6; Pred. = 10·8) 7·5 (SD ± 0·9; Pred. = 6·3) 4·5 (SD ± 0·7; Pred. = 2·7) 3·3 (SD ± 0·5; Pred. = 2·0) Soldiers discovering baits N/A 3/20 trials 0/20 trials 0/20 trials Mean proportion of soldiers recruited to baits N/A 16·8% (SD ± 11·6) 3·0% (SD ± 4·4) 1·0% (SD ± 2·2) POWELL, S., 2008

37. PHYLOGENETIC CONSIDERATIONS AND ANALYSES Ancestral character state reconstructions of nesting ecology and nest defence behaviours in the ant genus Cephalotes using four terminal taxa Numbers Ancestral node Reconstructed mean and standard deviation for standardized nest entrance area Terminal taxon Observed mean and standard deviation for standardized nest entrance area Bar (Reconstructed point ) Dark grey Loss of an attack strategy during nest Light grey Loss of worker involvement in nest entrance blocking POWELL, S., 2008

38. Termite Soldiers The colony is the adaptive unit, and selection for colony defence can drive the morphology and behaviour of soldiers to such extremes that they can no longer feed themselves ( Hölldobler & Wilson 1990) Termites plays – Essential role At the cost of reproduction and self maintnence .

39. Role of soldiers - Reticulitermes Examined the relative effectiveness of soldier defenses, and concluded that Reticulitermes soldiers were incompetent compared with Coptotermes soldiers. Soldiers are so few and do not use their cephalic sesquiterpenes against ants . Waller and LaFage (1986) ( Zalkow et al .,1981 ) Colony-level stabilization of soldier head width for head-plug defense in Reticulitermes speratus

40. The nests are divided into chambers connected by small openings that allow only one termite at a time to pass through. Chamber-by-chamber nest defense Deligne et al ., (1981 )

41. Soldier defense Combination of mandibular and head-plug ( phragmotic ) defenses that were complementary to the structure of the nest. MATSUURA, K., 2002

42. Soldier defense against ant predation Brachyponera chinensis MATSUURA, K., 2002

43. Phragmotic defense - Requires soldiers to have heads wide enough to block the small openings between each nest chamber. Too narrow : Allow enemies to pass through Too large : Would clog the openings How Stabilizing selection is acting upon?

44. Soldier head width was more stable than the size of other body parts, they compared the coefficients of variation (CVs) of head width and other body parts. ( Phragmotic defense requires a uniform head width) How to determine Stabilization ? Non- phragmotic soldiers Coptotermes formosanus Shiraki Nasutitermes takasagoensis Shiraki Rush out and assault intruders Free from head-width stabilization Phenotypic Variation

45. Size measurements and biometric analysis M aximum head width (HW ) Head length (HL) - Base of the mandibles to the posterior margin of the head H ead volume (HV) - (HW/2) 2 π x HL Maximum P ronotum width ( PW)

46. Head width Almost unimodal pattern Frequency distributions Pronotum width & Head length Bimodal patterns MATSUURA, K., 2002

47. Comparison of CV s b/w HW and other body parts Bars - CVs of pooled data of males and females . Closed bars - S ignificant difference from HW R. speratus soldiers MATSUURA, K., 2002

48. C. formosanus N. takasagoensis MATSUURA, K., 2002

49. Evidences for Phragmosis The small openings in a Reticulitermes nest were of relatively uniform size in the colony. The mean diameter of small openings in colony C was 1.23±0.03 (SD ) mm ( n =20). The CV of the diameter of small openings was 2.61, which was as small as the CV of soldier head width in R. speratus . MATSUURA, K., 2002

50. Termite genus Percenatge of Soldiers Mode of Defence Reticulitermes 3.59±2.50 ( n =108 ) Phragmosis Coptotermes 40 Rush out and assault intruders Evidences for Phragmosis MATSUURA, K., 2002

51. CONCLUSION Specialized defence traits can be the key feature of adaptive evolution They play a crucial role in surviving enemy attacks and in securing resources. Because it improves functional specialization (i.e., performance of a particular task) and ultimately yielding the fitness gains to the colony Selection is thought to favour the evolution of novel phenotypes.

52. THANKS