Evolutionary adaptation of plant traits to interact with animals innate behavioral responses leading to either mutual or antagonistic interactions benefiting plants in acquiring food, easing the job of pollination and seed dispersal and also in defense against biotic enemies.

1. Innate Receiver Bias-
Influencing the evolution of PLANT-ANIMAL Interactions
Presenter:
Bhavya, C.
ID. No. PALB 6075
Ph. D. in Plant Biotechnology
Department of Plant Biotechnology,
UAS, GKVK, BENGALURU-65

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3. Inside
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4. Receiver bias in plant–animal interactions
???
?. Selection on plants imposed by behavioral responses of
animals, where those responses have evolved in a context
other than the interaction with the plant - Schiestl, 2017.
?. Behavioral responses important in receiver bias can be based on-
Sensory mechanisms: ability to detect signals with a given
efficiency or
Based on neuronal or higher cognitive processes in the
perceiver’s brain (Naug & Arathi 2007)
?. Help us to understand different plant–animal interactions and
interpret their evolution, within and beyond better known
concepts such as mutualism, coevolution, or mimicry
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5. Innate (or rarely learned) responses to a signal in an interacting
animal
Responses in the interacting animal or related taxa having an
alternative function outside the interaction
(typically, such alternative functions are ancestral to the interactions—this
aspect is especially pointed out in the related concept of pre-existing bias)
Adaptive evolution of a signal in the plant, matching the
preference of the interacting animal.
(Adaptive evolution requires the demonstration that the signal is associated
with fitness gains and is an evolutionary novelty
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Concept of receiver bias

6. Animal responses evolving before the onset of a plant–
animal interaction
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Schiestl, 2017
Pre-existing bias: a form of receiver bias that explicitly implies an
evolutionary sequence (i.e., behavioral responses are
evolutionarily older than signals)
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7. Evolutionary novelty
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8. Orchid flowers resembling mating signals
of female insects
Mimicry evolved via male
preferences for sexual signals
The (innate) preferences for
sexual signals in males have
clearly not evolved in the context
of flower visitation
But rather that of mating
behavior, and the signals in the
plants are evolutionary novelties
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Anacamptis papilionacea var. papilionacea and
Anacamptis papilionacea var. grandiflora
Scopece et al., 2009
Anthophora crinipes

9. Receiver bias and mimicry
Receiver bias
 A process (i.e., an animal
selecting for a given signal
in a plant) that can lead to
mimicry or mimicry-like
resemblance
 Based on innate responses
Ex: plants emitting these
pheromones to repel aphids
Mimicry
 A pattern, namely the
adaptive resemblance of a
mimic to a model, evolving
under selection by an
operator
 Based on either innate
preferences or learning and
generalization
Ex: nontoxic plants producing
signals associated with
toxicity
Type of behavior in the interacting animal
(Wickler 1965; Darst and Cummings 2006)9

10. Receiver bias in pollination
Plant–pollinator interactions- highly generalized to extremely specialized and
from mutualistic to (rarely) antagonistic
Plant signals can be honest, indicating the amount of reward available- color,
flower and floral size and floral scent
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(Haverkamp et al., 2016)

11. Flower signals that likely evolved under
receiver bias
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Large size Naug&Arathi 2007,
Schaefer&Ruxton 2009
Sexual mimicry Ellis&Johnson
2010, Vereecken & Schiestl
2008
Imprecise imitations of conspecifics Goulson et al. 2009,
Pollenmarks Osche 1979
Patterns such as stripes peripheral dots,
and dark centers
Biesmeijer et al. 2005
Scent compounds primarily used as
insect pheromones or kairomones
Brodmann et al. 2008, 2009,
2012; Schiestl 2010; Schiestl
& D¨ otterl 2012

12. Heat production in flowers
Floral thermogenesis: plants able to raise temperatures
inside flowers to 35◦
C above ambient
Both gymnosperms (cycads) and angiosperms
Mostly among basal angiosperms- magnoliids and monocots
but are found only rarely in eudicots.
This trait is closely associated with pollinators, particularly
beetles and flies
Schiestl et al., 201712

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14. Is thermogenesis a costly trait ?
? Is its Adaptive significance
1. Increased volatilization of scent
2. Promotion of pollen and pollen tube development
3. Promotion of insect activity inside the chamber
4. A heat reward for insects
5. A temperature signal that insects associate with
rotting plant or animal material
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Dung or carrion oviposition mimicry systems
Floral Thermogenesis in Different Pollination Systems
Heat production can be found in both
 Rewardless (mimetic)
 Rewarding pollination systems
 Plants with nursery pollination systems
In thermogenic nursery pollination systems with unisexual
reproductive organs
Oviposition or larval development often occurs only in male
flowers and cones (Meeuse 1975)
Thermogenesis is usually found in both sexes (Ervik & Barfod 1999)
Heat might also have another function as signal to entice
pollinators to visit reproductive organs of both sexes
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16. Why do pollinators select for floral thermogenesis?
Evolution of floral thermogenesis in plants through receiver bias..
Plants employ oviposition mimicry-
Responses of pollinators to cues of oviposition sites and their
imitations are innate
The evolutionary pattern of thermogenesis shows that
thermogenesis evolved three times independently as an
evolutionary novelty in mimetic Araceae pollination systems,
closely associated with fly pollination.
?. Is temperature a reliable cue in dung or decomposing plant
matter, indicating its nutritional value for insects
?. Do insects that breed in dung, carrion, or decaying plant matter
use temperature as a cue
?. Are pollinators of thermogenic flowers generally closely related
to those that use larval substrates with elevated temperature
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17. Receiver bias in seed dispersal
Schiestl et al., 2017
TrilliumAfzeliaRicinus communis
Elaiosomes are adaptations co-opting nutritional and
sensory preferences of ants
Oleic acid as a signal to pick up and move dead
colony members suggesting an evolutionary
origin older than its signaling function in
elaiosomes
Needs to be tested by mapping the respective
functions on a phylogenetic tree of ants and the
plants with seeds dispersed by them
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18. Mimicry: Evolve without receiver bias; when fruit dispersers
have acquired (i.e., learned) preferences for a commonly
occurring fruit signal in a given community
Mimicry
Mimicry
Myrmecochory
?? !!!
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19. Ant gardens!!
Compound is rare in plants but
commonly produced by ants, in
which it has diverse functions,
suggesting its attractive
function in seeds has evolved
through receiver bias
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20. Mimicry driven by receiver bias- antagonism
The fruits emit several volatiles typical of herbivore dung,
which are known to be used by dung beetles to find their larval
substrate
The likely innate preference of beetles for these signals,
evolved within the context of reproductive behavior
Midgley et al., 201520
South African Ceratocaryum argenteum

21. Receiver bias in plant defense
Aposematic signals- Honest signals (Animals)
Alarm Pheromones in Defense
Schiestl et al., 2017
Wild potato (Solanum berthaultii) produces
large amounts of E-β-farnesene in
glandular hairs and by releasing it is able to
repel aphids from its surface
Alarm pheromone are innate and evolved in the context
of predator avoidance in aphids, and aphid alarm
pheromones in plants are likely evolutionary novelties
Gibson & Pickett 1983
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22. E-β-farnesene-induced in maize after herbivore attack : functions
as an indirect defense to attract the aphids’ enemies; indeed, the
volatile is attractive to predators and parasitoids of aphids
(Francis et al., 2005)
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23. Citral, neral, and
neryl formate-
mite species Shimizu et al. 2004
Geraniol nymphs of the lace
bug (Corythucha
marmorata)
Watanabe &
Shimizu 2015
Hexanal, 2-hexenal bug species Noge et al. 2015
The common plant volatiles:
as alarm pheramones
These chemicals overlap between plants and herbivores
deserve more experimental work to investigate their
functions
in
plant defense
as
well as
possible
applications in integrated plant protection
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24. Alarm pheromones in other contexts
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25. E,E- α-farnesene
(Willmer et al., 2009)
Little is known about their chemistry or whether they
evolved as honest signals within ant–plant interactions or
from ancestral functions in the ants’ biology under receiver
bias
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26. Case study 1
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27. Materials and methods
Field surveys of gall-feeding insects in 2001–2006
Field observations on visual animal mimicry by plants in central
Japan in 2010–2014
Three gall taxa were found to have strong visual similarity to
lepidopteran caterpillars
Search for galls bearing a caterpillar-like appearance was
performed using several pictorial and reference books of plant
galls in Japan and other regions, including
Yukawa and Masuda (1996), Usuba (2003), and Redfern (2011)
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28. Results
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29. Testing of the hypothesis and further prospects
The hypothesis may be supported If herbivory on galls or nearby
leaves is reduced when decoy caterpillars are placed around the
galls
Hypothesis predicts that caterpillar-like galls would suffer less
herbivory than dissimilar galls
Gall characteristics -
gall midges, gall wasps, jumping plant lice and gall mites are aggregated
and often red colored,
galls look like egg masses of Heteroptera, Coleoptera, and Lepidoptera or
aggregated aposematic larvae)
may function as defensive mimicry of aggregated herbivorous
or aposematic insects against other herbivores
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30. Case study 2
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?. Do visually oriented predators recognize objects that
resemble ant shape (myrmecomorphy) and avoid caterpillars
and fruit
?. The shape of ants alone is sufficient to prevent beneficial
predators that specialize on herbivorous insects and
interactions with frugivores
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31. Material and methods
‘Helia Bravo Hollis Botanical Garden’ located in the Tehuacan-
Cuicatlan Valley, Puebla, Mexico
Artificial ants on dummy caterpillars and fruits
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33. Conclusion
Importance of visual cues of body-form of ants in
interspecific interactions
Opens a new way to study the effects of ant presence
on caterpillar predation and fruit dispersal by testing
different ecological hypotheses in different
ecosystems around the world where ants are
remarkable organisms on plants
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34. Summary
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Major progress in applying this concept to plant–animal
interactions thus depends on integrating approaches that identify
Behavioral patterns of interacting animals
The evolutionary origin of these behaviors
Functional ecology and evolutionary patterns of key plant
signals.
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