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Use of Plant Resin by a Bee Assassin Bug Apiomerus flaviventris
(Hemiptera: Reduviidae)
Apiomerus flaviventris Herrich-Schäffer
Consuming the hemolymph or enzymatically pre-digested internal tissues of prey insects
Bee assassin bug
Active predator
Injecting venom
Southern California, Arizona, and Mexico
Study area: Anza Borrego Desert State Park (April to June 2006)
Distribution of A. flaviventris
http://www.desertmuseum.org
Association with Plant Resins
Adult female
Larvae
Resinous plants
Setae on Ventral Surface
Female
Male
Metatibial comb
Metatibial Comb
Collecting Brittlebush Resin
(A~C: resin collection, D: brittlebush resin)
Resin-covered Egg Mass
What do they do with the resin?
A. flaviventris oviposition
What do they do with the resin?
With plant resin Without access to resin
Use of Resin
Formation of tightly-packed egg mass
What do they do with the resin?
Resin on Egg Mass
Protect eggs against parasitoids
Prevent the eggs from desiccating
Deter egg predators such as ants
(Swadener and Yonke 1973, Szerlip 1980, Eisner 1988)
© Szerlip
Resin Deterrence Test
Forelius pruinosus Linepithema humile
Does brittlebush resin deter omnivorous ants?
(Choe and Rust 2007)
Resin-free eggs: more readily picked up and carried away by ants
Resin-coated preys: less preferred by omnivorous ant species
Does brittlebush resin deter omnivorous ants?
Resin Deterrence Test
(Choe and Rust 2007)
Feeding Deterrence… Why?
Stickiness?
Phytochemical property of the resin: chromene and benzofuran derivatives (Kunze et al. 1995)
Deterrent as well as toxic towards various herbivorous insects
Does brittlebush resin deter omnivorous ants?
First instar larvae collected resin from the outer surface of the egg mass, coated their foretibia with the resin
First Instar Larvae
Protect larvae against predators or help prey capture (Eisner et al. 2005)
In addition to the plant resin…
Ventral abdominal surface of a adult female without access to resin sources
(Barth 1963, Szerlip 1980)
Bugs produce their own secretion?
In addition to the plant resin…
Bugs produce their own secretion?
Numerous female specific pores on ventral-abdominal surface of female
Magnified glandular pores
In addition to the plant resin…
Bugs produce their own secretion?
Internally, small ducts are associated with the pores
In addition to the plant resin…
Bugs produce their own secretion?
Small ducts associated with the pores: part of glandular unit (Barth 1963)
In addition to the plant resin…
Bugs produce their own secretion?
© Barth© Barth
What are there in the secretion?
Resin-covered eggs
Resin-free eggs
Brittlebush Resin
TLC using 100% hexane solvent system
Non-polar compounds
Polar compounds
Hydrocarbons
Identification of the secretion
C23 11
Me-
C23
C 24 11M
e-C
24
C25
mo
no
ene
C2
5M
e-C
25s
C26
C2
7
C28
C2
9
Retention time (min)
GC-MS Analysis of Hydrocarbons
Resin-covered eggs
Resin-free eggs
Identification of the secretion
Higher amount of hydrocarbons in the resin covered egg mass
Major alkanes (C25, 27, 29) per egg 8 : 1
Major methyl-branched alkanes (Me-C23, Me-C25s) per egg
13 ~ 15 : 1
What are there in the secretion?
Identification of the secretion
Acknowledgments
Anza Borrego Desert State Park
Anza Borrego Foundation and Institute
California State Parks Colorado Desert District
Jocelyn Millar
Steve McElfresh
Douglas Yanega
Hyunchung Yoo
Not only resin, but also …
Summary & Discussion
Under UV CharredA: Resin-covered egg mass extract
B: Brittlebush resin
A B A B 3:1= hexane: ethyl acetate
• A: Extract of 44 eggs coated with brittlebush resin by a female bug
• B: Extract of 44 resin-free eggs
• 2 μl of each extracts spotted (i.e., each spot contains approximately 0.088 egg equivalent hydrocarbons)
Summary & Discussion
A B
Hydrocarbons