Plant Mites and Sociality_ life types in mites

Mites have become serious pests in agriculture and forestry as a side-effect of the excessive use of synthetic chemical compounds after World War II. Among plant mites, Tetranychidae and Phytoseiidae are the most general families and many studies have been conducted on these mites so far. The plant leaf is a kind of micro-sphere where various mites play evolutionary games such that we call them to plant mites in the same sense as aquatic and soil mites (Jeppson et al., 1975; Saito, 2010). Sociality is the degree to which individuals in an animal population tend to associate in social groups and form cooperative societies. Sociality is a survival response to evolutionary pressures. Spider mites are one of the simplest nest-building phytophagous organisms with varying sociality. The report about LW (little web), WN (woven nest) and CW (complicated web) life types strongly suggest that the life type of a spider mite reflects the evolutionary interactions between prey (spider mites) and predator (mainly phytoseiid and stigmaeiid mites), and can be regarded as type of antipredator adaptation (Mori and Saito, 2004; Yano et al., 2011).
In addition, the spider mites belonging to the genus Stigmaeopsis construct extremely dense oval woven roofs (web-nests) over depressions on the lower surface of host leaves and are known to have a kind of sociality. Four new life types (WN-p, WN-h, WN-n, and CW-g) in five species Stigmaeopsis temporalis Saito, S. tenuinidus Zhang, S. tegmentalis Saito, Neonidulus tereotus Beard and Walter, and Eotetranychus asiaticus Ehara are documented in relation to their supposed functions (Saito et al., 2015; Schausberger et al., 2021).
Four species that occur on bamboo plants in Japan, show different nest areas. The nest area of Stigmaeopsis longus (Saito) is the largest, followed by that of S. celarius Banks, S. takahashii Saito and Mori, and S. saharai Saito and Mori in decreasing order. Smaller nests effectively prevent adults of several predator mite species from intruding. Variation in nest structure may therefore influence the diversity in social organization (Mori and Saito, 2004).

1. 1
Seminar -I

2. Flow of presentation
2
1
•Introduction
2
•Classification of societies
3
•Nest-building and life type diversity in Spider mites
4
•Fecal manipulation behavior
5
•Genetic diversity
6
•Sex behavior: Male to male combat
7
•Kin Selection
8
•Summary and conclusion

3. Importance of the study
•Plant mites are plant inhabiting mites in common
•Champions of acaricideresistance
•Major pests of open and protected cultivated crops
•Having quarantine importance due to invasive nature
•Plant defense breakers
•Need of behaviouraland evolutionary study
3(Jeppsonet al., 1975; Saito, 2010; ZhifengXu et al., 2014)

4. Fig. 1. Systematic Overview of Acari
4

5. Peculiarities of Mites for Ecological
and Evolutionary Studies
•Microscopic
•Wingless
•Presence of silken threads
•Nest building
•Ballooning
•Colony formation-Cooperative, Kin selection
•r-k life strategy
•Arrhenotoky
5
(Saito, 1985)

6. Fig. 2. Various life histories known in Tetranychinaeexplained from the spatiotemporal stability
of host plants under 25°C, 50–60% RH (Saito and Ueno, 1979)
6
Why Spider mites are successful invaders?

7. How do they classify mite societies?
7(Crespiand Choe, 1997)
Table 1. Types of insect social systems
1.Brood care: parental and biparentalcare
2.Shared breeding sites: involve multiple females
3.Alloparentalbrood: behaviorally distinct groups
4.Castes : irreversibly behaviorally distinct at some point prior to reproductive maturity

8. 8(Schausbergeret al., 2021)
Tetranychusurticaefemale with egg Group of T. urticaefemales and their offspring
Tetranychuskanzawaifemale
E, F: Nests of Stigmaeopsislongus on bamboo leaves
T. urticaeand T. kanzawaifemales sharing web

9. 9
Little web type ( LW )
Aponychusfirmianae
Aponychuscorpuzae
Complicated web type ( CW )
Oligonychus
Schizotetranychus
Eotetranychus
Woven nest type ( WN )
Eotetranychussuginamensis
Eotetranychusshii
Schizotetranychusbrevisetosus
Fig. 3. Life Type Diversity in Spider Mites
(Saito, 1995; 2010)
Fig. 4. Empodialclaw variation among spider mite genera
Life Type Diversity in Spider Mites

10. 10
Fig. 5. Various life patterns observed in the genera of Tetranychidae. g, guy ropes; 1. next generation
(grandchildren); 2. feeding within and under web (Saito, 1995)

11. 11
Fig. 6. Various life patterns observed in the genera of Tetranychidae(Saito, 1995)

12. 12
Fig. 7. Various life patterns observed in the genera of Tetranychidae(Saito, 1995)

13. 13
WN-p life type appeared in Stigmaeopsistemporalis and
Stigmaeopsistenuinidus
WN-h life type appeared in Stigmaeopsistegmentalis
(Saito et al., 2016)

14. 14
WN-n life type appeared in Neonidulustereotus
CW-g life type appeared in Eotetranychusasiaticus
(Saito et al., 2016)

15. 15
(Saito, 1995; Saito et al., 2016)Fig. 8. Sub-life types
Fecalmanipulation behaviour

16. 16
(Sato et al., 2008)
Fig. 9. Typical WN-c life type of Stigmaeopsislongus inhabiting Sasabamboo leaf (SEM micrograph)

17. Fig. 10. Various social life patterns observed in three genera in Tetranychinae.
5. A different means of egg protection and quiescent stage is known; 6. feces are deposited
outside of nest; 7. outside of particular places near nest entrance; 8. inside of particular place(s) near nest
entrances; 9. web mat is made under eggs.
17

18. 18
Table. 2. Diversity in Genetic System
a. Mating is must for F+ reproduction, but the male genome is eliminated after fusing with the egg nucleus
b. Mating is necessary for the female to reproduce because egg embryo development is only activated by a sperm.
c. Brevipalpusphoenicis, which has this type of genetic system, is controlled by microorganisms
(Weeks et al., 2001)

19. Table. 3. Genetic systems in Tetranychidaeand its related families
19
(Helleand Pijnacker, 1985)
a. Unfertilized ovipositionand only male observed
b. In Oligonychusilicis, unfertilized females reproduce males, but sometimes they also produce females

20. 20
Sexual Behaviour
“mate guarding”
1.Precopulatoryguarding
2.Postcopulatoryguarding
(Potter et al., 1976; Sato, 2019)Fig. 11. Precopulatoryguarding

21. 21
Fig.12. Multiple male precopulatoryguarding in S. longus ( right )
S. miscanthimale killing conspecific male ( left )

22. 22
Fig. 13. Male-to-male combat in T. urticae
Male-to-Male combat

23. 23
Table. 4. Sociality of Stigmaeopsisspecies
(Mori and Saito, 2004)
Evidence of counterattack-weakest predator stage
Stigmaeopsiscelarius
1.Nest size is correlated with the effect of nest
defence (counterattack).
2.“altruistic”-Behaviour to protect offspring's from
adult predator
3.Escaping and biparentaldefence
4.Fecal management

24. 24
Fig. 14. Variation in nest size
(mean area ±SE) between Stigmaeopsisspp.
Fig. 15. Counterattack efficiency Stigmaeopsisspp. having
different nest sizes
( Mori and Saito, 2004)

25. 25
Fig.16. A hypothesis of predator mediated speciation in Stigmaeopsis
(Mori and Saito, 2005; Saito, 2011)

26. Variation in nesting behavior of spider
mites, Stigmaeopsishaving sociality
26(Saito, 2016)
Fig.17. Relation of dorsal setae in recognizing the nest roof
and nest size

27. 27(Mori and Saito, 2004)
Table. 5. Experimental design of counterattack effects

28. 28
Fig. 18. Comparison of counterattack efficiency among species
Fig. 19. Defenders reaction to intruder

29. 29
Fig.20. Survival curves of the intruder in experimental
groups of S. longus males or S. celariusmales versus
intruder
Fig. 21. Comparisons of efficiency of group defense
between S. longus and S. celarius
(Mori and Saito, 2004)

30. 30
Fig. 22. Hemicheyletiamorii(Left) using an optical microscope
Scanning Electron Microscopy (SEM) photo (right ) ( Mori et al., 1999).
Other than spider mites that have social behavior?
1.Silken nest formation
2.Colonies in web
3.Egg laying on web mats
4.Sit and wait predation
5.Cooperative predation
6.Nest sanitation

31. Kin Selection
31
Fig.23. Variation in Male Aggressiveness between species
Two adult males of S. miscanthiin fighting
position, facing each other with front legs
spread out, inside a nest
(Saito, 1990; Sato et al., 2018)

32. 32
Fig. 24. Difference in size of leg I between winners and losers
in male-to-male combat of S. miscanthi(Saito, 1990)

33. 33
Table. 6. Winning probability between different-aged males or in the order
of nest occupying male (owner or intruder).

34. 34
Table. 7. Death probability and time until death on one of paired males in
kin-paired and stranger-paired male-to-male combat of
Stigmaeopsismiscanthi
(Saito, 1994)

35. 35

36. 36

37. 37

38. 38
Yezonychussapporensisshow egg and quiescent larva positioning on
the tips of leaf hairs
Schizotetranychusreckimakes compartment-type nests