Natural Enemies Orienting to Melanaphis sacchari

J.P. Michaud and Felipe ColaresKansas State University

Sorghum – Sugarcane Aphid Research Exchange Meeting

New Orleans, LAJanuary 7 – 8, 2016

Introduction

Are native predators pre-adapted to find SCA?Or do they need to evolve novel responses to

find a novel prey?

Hypothesis:

Aphid natural enemies will recruit more quickly and in larger numbers to a familiar prey (S. graminum) than to a novel prey (M. sacchari)

Materials & Methods

• Potted sorghum plants infested with EITHERM. sacchari (SCA) or S. graminum (GB)

• 2 field locations (tree line vs sorghum monoculture)

• All insects counted daily on all plants untilaphid colonies consumed

• Data tallied as ‘No. life stage-arthropod-days’

The tree line cohort

The sorghum cohort

The tree line cohortN

o. a

phid

s / p

ot

Observation date

No colonies of either aphids species matured

Tree line cohort – major predators

Observation date

The sorghum cohortN

o. a

phid

s / p

ot

Observation date

No colonies of either aphids species matured

No.

coc

cine

llid

adul

tsN

o. c

hrys

opid

larv

aeThe sorghum cohort – major predators

Observation date

C. carnea was the only dominant species equally present in both cohorts

No. arthropod life stage-daysTree line cohort Sorghum cohort

Natural enemies Life stage GB SCA GB SCA

Aphelinus sp. adults 0 4 8 4

mummies 22 41 771 319

Chamaemyiidae larvae 0 24 0 0

Chrysoperla carnea adults 3 12 10 34

eggs 194 609 204 401

larvae 3 19 35 97

Coccinellidae adults 0 3 58 64

egg masses 0 8 2 97

larvae 0 77 2 24

Erythraeus sp. (mite) nymphs 12 5 0 0

Hemerobiidae adults 0 0 0 1

eggs 0 181 0 0

No. arthropod life stage-days

Cohort 1 Cohort 2

Life stage GB SCA GB SCA

Lysiphlebus sp. adults 2 5 0 0

mummies 47 0 771 0

Orius insidiosus adults 0 0 39 11

nymphs 0 0 104 22

Syrphidae adults 5 9 0 0

eggs 1308 1626 13 37

larvae 631 1278 33 60

pupae 0 5 0 1

Conclusion: There were more differences between locations thanbetween aphid species in natural enemy recruitment

Key Findings (data not shown)

• Relative suitability of SCA versusGB as prey (lab studies)

• Tested: H. convergens, C. maculata, C. carnea and O. insidiosis

• Results: SCA was equivalent to GB, i.e. supported development and reproduction of these species just as well

Key Findings• No real differences in NE responses

to SCA vs. GB

• ‘Natural’ biocontrol of SCAshould evolve similar to GB

• Efforts to conserve native NE’swill assist this process