Predators are one of the most important aspects of biologial control of crop pests. The predators may be insects or mites or nematodes or any other living organisms. Like the parasitoids, predators also follow a typical prey selection strategy. It includes Prey Habitat Selection, Prey Finding, Prey Acceptance and Prey Suitability. Prey Habitat Selection can be obtained by different plant odors or prey odors (like- honeydew, prey frass etc) or herbivore induced plant volatiles (HIPV). The HIPV is the most of important and reliable one to select the prey species by the predators. Actually when a plant is attacked by the pest species, the defense system is activated and it includes production of de novo or phytoalexins or secondary plant metabolites of various odors which actually attract the predators. Like- the bean plants attacked by Tetranychid mites, are attracted by the predatory Phytoseiid mites. Besides plants attacked under pests, release Methyl Salicylate like molecules which also attracts predators like Chrysopa spp. After habitat finding, the predators forage for suitable prey and if initial inspection of the habitat leads to evidence of prey in the local area, the predator is likely to engage in Intensified Local Search (ILS). ILS includes frequent turning, sinous search paths and slower walking. Theere are a number of factors which influence the efficiency of ILS. These include- Host Plant Architecture, Surface Texture of Plants, Hunger Status of Predators, Visual Cues, Patch Quality and Prey Products. Like- Larvae of some ladybirds foage less frequently for aphids on highly branched varieties than on normal branched varieties of crops. Similarly waxy surfaces can reduce their foragig efficiency and some of the predators are entrapped and died within the trichomes. Native adults of Harmonia axyridis are more attracted to yellow colour as compared to green colour. They are also attracted to the surface treated with prey products like honeydew to search for the preys while there are lots of exceptions regarding this. After a prey has been contacted, the age and experience of the predator, size of the prey and prey's defensive actions can influence the success of attack. The acceptance of prey depends on certain features like- food habit of the prey, chemical composition of prey cuticle, warning colourations and gregarious nature of prey species. After the acceptance, the suitability of prey is important to determine. This depends on- whether it supports both developement and reproduction or only developement or unpalatable. Suitability of prey for immature stages of predators depends on the survivorship of them, developemental time and adult body weight. Indexing prey suitability for mature adults depends mainly on the reproductive capability, high fecundity and viability. If predators feed on diseased or paralyzed hosts, it may induce low body weight, low immunity and survivorship. This understanding helps in successful IPM bio-control

1. Prey Seeking Behaviour of Predators
By-
Sourav Chakrabarty
Division of Entomology
ICAR-IARI, New Delhi

2. INTRODUCTION
 The behavior by which one animal kills and devours another
species is called Predation and that animal is called a Predator.
 The motivation of predatory behavior comes generally from
hunger.
 The temporal and spatial synchrony between predators and prey
availability is important for successful biological contol and these
results will highlight a novel role in predator foraging behavior
(Tentelier and Fauvergue, 2007).

3. OBJECTIVES
 Reviewing the prey seeking behavior of
predators and use them as a cue to best predator
selection with a good character of prey location.
 To launch or incorporate such behavioral
studies in the research system to select best fit
biocontrol agents.
 To explore the advances in predator study
and its use for general pest management.
 To be introduced with different prey seeking
behavior of predators and to use them in the
integration of IPM.

4. Prey
Seeking
Habitat
Location
Prey Finding
Prey
Acceptance
Prey
Suitability
COMPONENTS OF PREY SEEKING
BEHAVIOR

5. PREY HABITAT LOCATION
 The Habitat (e.g. plants) itself
 The Prey itself
 Chemicals released by the pest damaged plants

6.  The predator is attracted to the odors
from the bodies of the prey like-
pheromones or prey frass etc.
PREY ODORS- A ROUTE MAP FOR
THE PREDATOR!
Fig:-
Rhizophagus
grandis
Fig:-
Dendroctonus
micans
Fig:- Chemical cocktail
Fig:- Response of Predator towards
the cocktail

7.  The plants actively being damaged by the herbivorous prey are both
reliable and highly detectable as they are produced in large quantity.
 The plant, affected by herbivore, actively releases some phytoalexins
(HIPV) that can attract certain predators to find their habitat.
 Gomez- Cabezas et al. (2023) has described the phenomenon of
affected plants as “CRY FOR HELP”.
HERBIVORE INDUCED PLANT
VOLATILES (HIPV)

8.  Plants damaged by Spider Mites, are
highly favored by the predatory
Phytoseiid Mites (Sabelis & Van de
Baan 1983).
EFFECT OF HIPV- BEAN PLANTS,
SPIDER MITES & THEIR PREDATORS
Fig:- Effect on Density and Attractiveness of Plant Volatiles on Pest (left)
and Predator (Right)

9.  Predators may respond to the mixtures of odors that include both
herbivore-induced plant volatiles and volatiles from the prey itself.
 Hydrophilid Beetles that are generalist predators of Banana
Weevil, Cosmopolites sordidus (Germar), are attracted to weevil-
damaged banana pseduostem.
 The attraction is even much stronger if weevil aggregation
pheromones are also present.
PREY ODOUR + HIPV- A DEADLY
COMBINATION!
Odour from
infested
stem
Weevil
Aggregation
Pheromone
Predator
Attraction

10. Ladybird Beetle Prey Species
Host
Plant
Infochemical References
Coccinella septempunctata Aphis glycines Soybean
Methyl
Salicylate
Zhu & Park
(2005)
C. septempunctata Toxoptera aurantii Citrus Benzaldehyde
Han &
Chen
(2002)
C. septempunctata - - (Z)-jasmone
Birkett et
al. (2000)
C. septempunctata - -
(E)-B-
farnesene
Al Abassi
et al. (2000)
Hippodamia convergens Myzus persicae -
(E)-B-
farnesene
Acar et al.
(2001)
Adalia bipunctata
Acyrthosiphon
pisum
-
(E)-B-
farnesene
Francis et
al. (2004)
DIFFERENT PLANT INFOCHEMICALS
ATTRACTING CERTAIN COCCINELLID BEETLES

11. PREY FINDING
 After predators arrive at a suitable prey habitat, they must
locate their food, i.e. the “Prey”.
 If initial inspection of the habitat leads to evidence of prey in
the local area, the predator is likely to engage in Intensified
Local Search (ILS).
 Such behaviors can be triggered by prey frass, honeydew,
volatile and non-volatile cues or vibrations from prey chewing or
short range visual detection.
ILS
Frequent
Turning
Sinous
Search
Paths
Slower
Walking

12. FACTORS INFLUENCED EFFICIENCY
OF ILS
 Host Plant Architecture
 Surface Texture of Plants
 Hunger Status of Predator
 Visual Cues
 Patch Quality
 Prey Products

13. HOST PLANT ARCHITECTURE
Larvae of ladybird, Coccinella septempunctata forage less frequently
for Pea Aphids, Acyrthosiphon pisum on highly branched varieties than
on normal branched varieties of peas (Legrand and Barbosa, 2003)

14. SURFACE TEXTURE OF PLANTS
(A) Colony of the aphid, M. mentzeliae. (B) Single aphid, closeup. (C–I) The coccinellid, H.
convergens, on M. pumila: (C) egg cluster (arrow denotes site where egg has been injured by
trichomes); (D) entrapped larva (dead); (E) pupa (live), amidst colony of M. mentzeliae; (F) entrapped
adult, struggling to free itself (left hindleg is being restrained by a single trichome, hooked to tarsus);
(G–I) three adults that were entrapped and died (arrows denote clotted blood.)

15. VISUAL CUES
 A major established fact that helps to locate prey.
However, it is rarely looked upon.
 Many predators prefer to forage during daytime, as they can use the
visual cues to find prey.
 Native adults of Harmonia axyridis are more attracted to the yellow
pillars compared to the green pillars (Mondor and Warren, 2000).
Fig:- Effects of Color Pillars on Number of Visits of the Coccinellid, Harmonia axridis

16. PATCH QUALITY AND PREY PRODUCTS
 Patch Quality and Prey Products are very important to
find preys by the corresponding predator.
 Many a time it is found that prey products (like-
honeydew) are acting like a secondary cue that increases
searching efficiency.
ATTRACTION

17. NEGATIVE EFFECTS OF HONEYDEW
ON THE PREDATOR
 Presence of honeydew in patches
of Pear Psylla, Cacopsylla chinensis
can disrupt the searching and feeding
of their predator, Opius sauteri
(Zhang et. al 2019)
Reduced
Consumption by
Predator

18. PREY ACCEPTANCE
 After a prey has been contacted, the age and
experience of the predator, size of the prey and prey’s
defensive actions can influence the success of attack.
 The acceptance of prey depends on certain features-
 Food habit of the prey
 Chemical Composition of Cuticle
 Warning Colorations
 Gregarious nature of prey species.
ACCEPT
REJECT
Predator
Prey

19. FOOD HABIT OF THE PREY
 There are certain insects which feed on the toxic food
plants.
 They can able to sequester specific toxic alkaloids from
their food plant.
 The natural enemies, destined to feed on it, become
uninterested due to their toxic flesh or body sap.
 Thus, the prey can not be accepted by it’s predator and
the prey saves itself.
WE ARETOXIC!!
Fig:- Acyrthosiphon nipponicus

20.  One set of Milkweed bugs
are reared on Sunflower
Seeds (Palatable) and another
set on Milkweed Seeds
(Toxic).
 After 2 weeks, it was found
that toxic bugs are less likely to
be attacked by the Jumping
Spider.
Fig:- (left) Milkweed Bug and Nymph,
(right) Jumping Spider eating on Bug
MILKWEED BUG vs JUMPING SPIDER

21. CHEMICAL COMPOSITION OF CUTICLE
 Chemical Composition of prey cuticle
can alter the effect of their acceptance by
the predator.
 There are some insects which can
sequester toxic molecules from their food
plant and store them in cuticle as a mean
of defense.
 The larvae of Uresiphita reversalis can
sequester Quinazolidine compounds from
their leguminous hosts, which can deter
the predators.
Fig:- Larva of Uresiphita reversalis

22.  Extracts of the late instar larvae of
Uresiphita reversalis, were applied to one
set of Potato Tuber Moth larvae (image
given beside) and another set is left
untreated.
 The treated samples were deterrent to
both predators (images given below).
Fig:- Mischocyuarus flavitarsus Fig:- Iridomyrmex humilis
POTATO TUBER MOTH vs PREDATORS
Fig:- Phthorimaea operculella

23. WARNING COLORATIONS
 Cuticular colorations of prey’s body
(Aposematic Coloration) acts as an
important factor whether the prey is
accepted or not.
 Many a times, prey develops warning
colorations or mimics in such a way to be
avoided or repelled by the predators.
 The caterpillars of Cinnabar Moth
(Tyria jacobaeae) have alternate orange
and black bands down their bodies which
advertise the fact that they are poisonous
to eat.
Fig:- Larva of Tyria jacobaeae

24. GREGARIOUS NATURE OF PREY
SPECIES
Fig:- Chromacris lubber Fig:- Morpho sp caterpillars

25. PREY SUITABILITY
Suitability depends on the food, like-
 Whether it supports both development and
reproduction.
 Whether it can be eaten but doesn’t support
reproduction.
 Whether it is unpalatable or noxious that are not
eaten.
Suitable
• Less mortality
• Larger females
Not
Suitable
• Smaller size
• Lays fewer
viable eggs

26. Prey Suitability
for Immature
Stages
Survivorship
Developmental
Time
Prey Suitability
for Mature Adults
Adult Weight
Reproduction
and Fecundity
INDEXING PREY SUITABILITY FOR
IMMATURE AND ADULT STAGES

27. WHAT IF THE PREY IS PARASITIZED OR
PARALYZED?
 Diseased/ paralyzed or parasitized preys are not suitable for
the specialized predators as a meal.
 Larvae of Hippodamia convergens, fed on the mummies of
Schizaphis graminum parasitized by Lysiphlebus testaceipes,
fail to form viable pupae.
Low body weight, low
immunity, low
survivorship
Fail to complete all
developmental stages
Low Reproductive
capability, inability to
produce viable offsprings
Even causing
DEATH
Predator feeds
on diseased
host

28. PREY MANIPULATION BY PREDATORS
A
B C D
A. Conical Pits made by Antlion grubs.
B. Raptorial Forelegs of Preying Mantis.
C. Modified Labium (Mask) in Odonate
nymphs.
D. Elongated Antennae in larvae of
Chaoborus.

29. CONCLUSION
 Predators are widely used group of natural enemies as
biocontrol agents.
 Understanding the info-chemical exploiting strategies used
by foraging predators, it’s necessary to study plant-prey-
predator interactions in different scales in the field.
 Behavioral and electrophysiological investigations provide
information on the identity of chemicals that predators use
(Pettersson et al. 2008).
 Successful establishment of imported species may be
greatly facilitated if the release is designed so that predators,
especially females will have the greatest chance of locating
suitable prey as quickly as possible.

30. REFERENCES
 Al Abassi S, Birkett M.A., Pettersson J (2000). Response of Sevenspot
Ladybird to an aphid alarm pheromone and an alarm pheromone inhibitor is
mediated by paired olfactory cells. J Chem Ecol 26: 1765-1771.
 Legrand A., Barbosa P (2003). Plant Morphological Complexity impacts
foraging efficiency of adult Coccinella septempunctata L. (Coleoptera:
Coccinellidae). Journal Environmental Entomology 32 (5): 1219-1226.
 Miguel Gomez-Cabezas, Maria-Jose Romero, Julia K Prado (2023).
Understanding the Searching Behavior of Predators and Parasitoid Insects:
A Review. International Journal of Agriculture and Environmental Science
Volume 09, Issue- 01.
 Roy Van Driesche, Mark Hoddle, Ted Center. Control of Pests and Weeds
by Natural Enemies- An Introduction to Biological Control.
 Yang Ge, Pingping Liu, Liu Zhang, Synder W.E. (2019). A Sticky
Situation: Honeydew of Pear Psylla disrupts feeding by its Predator, Orius
sauteri. Journal Pest Management Science 76(1).