Interspecies aggression and social dominance in crayfish

84 Pages·2009·0.4 MB·English

by  Xin Luan

INTERSPECIES AGGRESSION AND SOCIAL DOMINANCE IN CRAYFISH

Xin Luan

A Dissertation
Submitted to the Graduate College of Bowling Green
State University in partial fulfillment of
the requirements for the degree of

DOCTOR OF PHILOSOPHY
December 2009
Committee:
Paul Moore, Advisor
Verner P. Bingman
Graduate Faculty Representative
Sheryl Coombs
Paul Morris
Thomas Kinstle
© 2006
Xin Luan
All Rights Reserved
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ABSTRACT

Paul Moore, Advisor

Interspecies aggressive competition was proposed to exist in closely related
species with niche overlap. However, the relationship between inter-intraspecies
aggressive competitions is unknown. Specifically, the cost in intraspecies aggressive
competition could be reduced when the aggression became ritualized, and could be
reduced further with the establishment of social dominance. It is unknown whether or not
such mechanisms exist in interspecies interaction. Three related crayfish species
Orconectes rusticus, Orconectes virilis, and Procambarus clarkii were used as a model,
we began to answer questions concerning the interspecies aggression in closely related
species with niche overlap. The work presented here shows that first, interspecies
aggression in crayfish appears to be ritualized and follows similar behavioral steps of
escalation as intraspecies aggression (Chapter II). Second, dominance relationships can
be established across species and these dominance relationships appear to last for some
period of time (Chapter III). Finally, there is some indication that previous fight
experience and status recognition may be an important part of interspecies interactions
(Chapter IV). Taken together, these results suggested that the patterns of aggressive
behavior in these three crayfish have evolved from the aggressive behavior of the
common ancestor of crayfish.
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ACKNOWLEDGMENTS
I am very happy to express my deepest gratitude to my advisor Dr. Paul Moore. I
would like to thank him for his guidance, patience, encouragement, and understanding in
these four years. Paul is not only a good advisor with enthusiasm and preciseness for
science but also a good friend with optimism, which encouraged me when I had hard
time in these four years. I also like to thank my committee members Dr. Vern Bingman,
Dr. Sheryl Coombs, Dr. Thomas Kinstle, and Dr. Paul Morris for their stimulating
conversations, encouragement and suggestions. I would like to thank all of the past and
present group my lab mates from the Laboratory for Sensory Ecology, Mary Wolf, Art
Martin, Rachelle Belanger, Kandice Fero, Christine Johnston, Adam Jansen, Peter
Ferrante, Michelle Cook, Jenny Chaffin, Sarah Dariano, Dan Percival, and Jenn Bergner.
They helped me in many ways in the past four years. I want to thank my friend Dan Wu,
who helped me with writing.
I give my sincere gratitude to my family, my wife Ying Deng, my parents
Yongdao Luan, Anguo Bian, and my parents-in-law Naigang Deng, Hongjun Sun. They
have been patient, positive, and helpful in their own way, has given me the courage and
inspiration to persevere.
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TABLE OF CONTENTS
Page
CHAPTER I. GENERAL INTRODUCTION ...................................................................... 1
CHAPTER II. A COMPARISION OF INTERSPECIFIC AGGRESSION ACROSS
THREE DIFFERENT SPECIES OF CRAYFISH ..................................................... 8
Introduction .......................................................................................................... 8
Materials and Methods ............................................................................................... 11
Results ........................................................................................................... 13
Discussion ........................................................................................................... 15
CHAPTER III. MAINTAINCE OF INTERSPECIFIC DOMINANCE
RELATIONSHIPS IN THREE SPECIES CRAYFISH ........................................... 18
Introduction .......................................................................................................... 18
Materials and Methods ............................................................................................... 20
Results ........................................................................................................... 23
Discussion ........................................................................................................... 24
CHAPTER IV. RECOGNITION OF DOMINANCE STATUS IN INTERSPECIFIC
AGONISTIC CONTESTS ......................................................................................... 27
Introduction .......................................................................................................... 27
Materials and Methods ............................................................................................... 29
Results ........................................................................................................... 33
Discussion ........................................................................................................... 36
CHAPTER V. SUMMARY AND GENERAL DISCUSSION ............................................ 41
LITERATURE CITED .......................................................................................................... 45
APPENDIX A. FIGURE AND TABLES ............................................................................. 57
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LIST OF FIGURES/TABLES
Figure/Table Page
2-1 The percentage of fights initiated and won by O. rusticus in all crayfish pairings ... 57
2-2 The average maximum intensity level reached in all crayfish pairings ..................... 58
2-3 The average fight duration in all crayfish pairings .................................................... 59
2-4 The time it took to reach intensity level two and level three in all crayfish pairings 60
3-1 The percentage of trials won by previous winner after preconditioning ................... 61
3-2 The percentage of trials initiated by previous winner after preconditioning ............. 62
3-3 The average maximum intensity level reached in subsequence fights ...................... 63
3-4 The average fight duration in subsequence fights ..................................................... 64
3-5 The time it took to reach intensity level two in subsequence fights .......................... 65
3-6 The time it took to reach intensity level three in subsequence fights ........................ 66
4-1 The setting up of chemical lesion .............................................................................. 67
4-2 The changing of percentage of trials won by the previous winner. ........................... 68
4-3 The changing of percentage of trials Initiated by the previous winner ..................... 69
4-4 The changing of maximum intensity level reached in the three days fights .............. 70
4-5 The changing of fight duration in the three days fights ............................................. 71
4-6 The changing of time it took to reach intensity level 2 in the three days fights ........ 72
4-7 The changing of time it took to reach intensity level 3 in the three days fights ........ 73
4-8 The relationship of factors affecting crayfish dominance ......................................... 74
4-9 Studies on the impact of chemical signals and fight experience on dominance ........ 75
1 Crayfish ethogram codes............................................................................................ 77
2 Statistical results for the percentage of trials initiated and won by previous winner
in the subsequence fights ........................................................................................... 78
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CHAPTER I
GENERAL INTRODUCTION
In many habitats, competition between organisms arises when resources are
limited (King 1973). Competition can occur for a number of different resources, such as
sunlight, water, or nutrients. Wheat and wild oat compete for sunlight in multistory plant
canopies (Barnes et al. 1990). Leuceana leucocephala and Senna siamea compete for
nutrient in the tropics where nutrients are a limiting factor (Oyetunji et al. 2008) and
soybean, cowpea and pigeonpea compete for water resources in agricultural systems
(Likoswe and Lawn, 2008). Like plant systems, animals also compete for limited
resources. In intertidal systems, blue crabs Callinectes sapidus compete with each other
for food resource of clam, Mercenaria mercenaria (Clark et al. 1999; Fiorenza 1997).
The male Buzzard Buteo buteo competes for territories that are necessary for building
nests and attracting mates (Kruger 2004). Crayfish inhibit other crayfish from occupying
shelters that protect them from predation (Martin and Moore 2007). Finally, within the
African wooded savannah, many animals such as lions Panthera leo, buffalo Syncerus
caffer, elephant Loxodonta africana, giraffe Giraffa camelopardalis, wildebeest
Connochaetes taurinus and zebra Equus burchelli compete for limited water (Loveridge
et al. 2006). Competition is the behavioral mechanism that underlies access to limited
resources.
A single organism could arise to be a superior competitor and limit or exclude
access to resources for other organisms (Wilson 1975). For example, the parasitic wasp
Trichogramma evanescens lays eggs on a host and excludes other wasps from gaining
access to this host (Salt 1936). In competition for light resources, wheat and wild oat
leafs shield sunlight from reaching other plants that potentially grow in their shade
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(Barnes et al. 1990). In African wooded savannah, lions will exclude access to water
resources for other animals in drought season (Loveridge et al. 2006). To exclude other
organisms from resources, superior competitors use many different types of competition
(Lotka 1932).
To gain access or to control access to resources, organisms have different types of
competition, ranging from non-aggressive competition to competition with different
levels of aggression (Schoener 1983). As non-aggressive competition examples, Daphnia
pulex (Water flea) and Ceriodaphnia reticulate (Water flea) compete for food resource
by consuming food resources at higher rates and thus, depriving other individuals the
nutritional potential of that food (Lynch 1978). Musculium securis (Pond Fingernail clam)
occupies space that prevents the competition from utilizing this resource (Mackie et al.
1978). Besides these mechanisms, aggressive competition, mediated by physical or non-
physical interaction between individuals, is fairly common in natural habitats.
Aggression has been defined in many classic biological papers starting in the
1970’s. For example, King (1973) defined aggression as “all behaviors associated with
the contest or struggle between individuals.” Wilson (1975) developed the meaning of
aggression from the vernacular sense and defined it as “an abridgment of the rights of
another, forcing him to surrender something he owns or might otherwise have attained,
either by a physical act or by the threat of action.” Based on these definitions, I will
define aggressive competition as a combination of the definitions of aggression and
competition; aggressive competition is the physical (or non-physical) interaction or threat
of action between organisms to gain or to exclude access to a limited resource. Examples
of aggressive competition include blue crabs Callinectes sapidus that were found to
physically attach each other to exclude the opponent from acquiring food resources
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(Clark et al. 1999) and walnut trees (Juglans regia) that produce toxic chemicals to
inhibit the growth of potential competitors (Auyong et al. 1963). The result of this
aggressive competition is access to limited resources.
Many different animals use aggression to regulate resource allocation. For
example, two ant species Oecophylla longinoda and Anoplolepis longipes engage in
aggression to determine territory control (Way 1953). Lions control water resources
during the drought season in the savannah (Loveridge et al. 2006). Crayfish limit access
to shelters by engaging intruder crayfish in agonistic encounters (Martin and Moore
2007). The benefits gained through aggressive competition have associated costs as well.
Costs associated with aggression can range from relatively minor energetic or
temporal costs to potentially lethal costs (King 1973, Case and Gilpin 1974). An
energetic cost refers to the energy expenditures during aggressive interactions which
causes the depletion of stored energy reserves (Enquist and Leimar 1990). Temporal cost
refers to the loss of time spent on the activities such as foraging due to time spent in
aggressive encounters (Isvaran and Jhala 2000). Potentially lethal costs may come from
the possibility of injury during aggressive encounters or the indirect effects such as
attracting predators. Generally, the end result of these costs is reduced fertility and
increased mortality (King 1973). Engaging in fights can be energetically expensive
because dominate individuals often spend a greater amount of time engaging in
interactions to maintain their dominate status (Kou et al. 2006). The possibility of injuries
and increased predation risk affect both winners and losers in these encounters. One
possible mechanism to reduce costs associated with aggression is to ritualize encounters
(King 1973).
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Ritualized behavior refers to a set of actions that serve as signals of different
levels of aggression (King 1973, Bruski & Dunham 1987, Eibl-Eibesfeldt 1977). Snakes
such as colubrid snake Chironius bicarinatus have ritualized behaviors such as pushing,
topping or entwining instead of biting as mechanisms of intraspecies competition
(Almeida-santos and Marques, 2002). Goats have ritualized behaviors such as rushing
and horn clashing instead of striking soft body parts with horns (Matsuzawa and Shiraishi
1992). The allied rock-wallaby, Petrogale assimilis have ritualized aggression act of 'tail
bite' (Barker 1990). Ritualized behavior has been theorized to enable organisms to
determine the outcome of interactions with lower investments of energy within a fight
(King 1973?). By avoiding higher intensity and potentially damaging encounters, the
actual cost of aggressive competition is reduced, thus increasing the fitness benefit of the
encounters. One of the key features of ritualized aggression is the presence of highly
stereotyped signals (Lorenz 1966).
Stereotyped signals refer to a behavioral sequence, which may be fixed in form
and orientation, and that served to transfer information, particularly, during aggressive
encounters (Dantzer 1986; Morris 1966). The variation of stereotyped behavior across
population may be very limited (Byers 1995). For example, brown howlers monkeys
(Alouatta fusca) use loud calls during aggressive interactions (Garcia Chiarello, 1995).
Chemical signals are used by crustaceans such as lobsters and crayfishes during agonistic
interactions (Moore 2007). Although stereotyped signal systems were found mainly in
intraspecific interactions, some stereotyped signals were found to be used in closely
related species (Jenssen 1977) or in species coexisting in habitat (Frix et al. 1991).