Fatal Attraction:

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Fatal Attraction

• Blister beetle larvae cooperate to practice mass
  deception in the
• Mojave Desert
• Leslie Saul-Gershenz
• Center For Ecosystem Survival
• J. Millar, U. C. Riverside

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Mass Deception

• A hitchhikers guide to the Mojave Desert
• Leslie Saul-Gershenz
• Center For Ecosystem Survival
• J. Millar
• University of California, Riverside

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Meloid Larva Morphology
Larvae disperse seek food
Eggs laid in or near bee burrows
Meloe larvaclimb onto vegetation
Meloe
Hornia
Cysteodemus
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Meloe franciscanus Habropoda pallida
distribution
Habropoda pallida
Meloe franciscanus
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Bee-witched and bee-lievable
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Host finding behavior
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Questions

• How do triungulin aggregations attract bees?
• Illicit signaling
• 1. Visual mimicry size, color, location, plant
• 2. Olfactory mimicry
• 3. Auditory mimicry

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Visits to models, masses dead bees
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Visits Hits
visits hits mean(V/H)
aggregations 98 5 obser. 2/lt1 dead
female 24 12 5/27 Live female 7 4
7/411 live female (caged) 125 0 19/1
hr Model of aggreg. 0 0 0 Dead male 0 0 0
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Visual mimicry
Bee Triungulins Size 8.5 mm 8.38
mm P.2448 Color gray-black red-brown Height
44.63 cm 28.13 cm 22-55 on plant 22-69
cm 10-55 cm overlap Plant perches overlap of
species used
not sign.different (Mann-Whitney U test, U157,
Z-1.163, P.2448, n20). Kolmogorov-Smirnov
(goodness of fit) -distribution of aggregation
lengths was significantly different than the
distribution of female bee abdomen lengths. (n
20), DF2, chi square 8.1, Plt.05).
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How to hitch a ride in the Mojave Desert

• Blister beetle larvae practice mass deception

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Cooperative Aggressive Mimicry
Behavior observ.
Mass stayed aggregated 27 events Mass moving
up or down on plant stem 14 events Mass moved to
different stem together 3 events Mass reformed
after knocked down 4 events
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Chemical profiles of female bees and
triungulinsTo bee or not to bee
Femalebee Triungulins
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Host location system

• Blister beetle larvae practice mass deception
• 1. Triungulins emerge and aggregate.
• 2. Triungulins cooperate to mimic female H.
  pallida.
• 3. Triungulins attract H. pallida male to
  pseudocopulate and then attach en masse during
  contact.
• 4. Triungulins travel by phoresy on male bee and
  transfer to female bee via venereal
  transmission.
• 5. Triungulins reach bee nest via phoresy on
  female H. pallida.
• 6. Triungulins mimic female bees both visually
  and chemically.

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Factors affecting the evolution of host location
behavior in parasitoids
Abundance and density of the host from the point
of view of the parasitoid Bees are a patchy,
mobile resource. Annual abundance and
distribution varies from year to year. Nectar
source location is unpredictable because of dune
habitat patchiness and heterogeneity. Human
activities can disturb host plants (fire, grazing
soil compaction). Selection pressures on
parasitoid and its searching behavior Sand
substrate temperatures reach 50 C. Larva have
a greater risk of desiccation as an
individual. Eggs at plant base are at risk of
exposure from wind and shifting
sand. Synchrony of intersection Host location
window is affected by annual patterns of
precipitation, temperature and wind. Bee
nesting varies with Larrea bloom onset.
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• Ecosystem Interactions

Kelso Dunes
Sidewinder
shelter
Petalonyx
Grasses
Larrea
Perching
Perching
Perching
Herbivore
Eggs
Eggs
Nectar/ pollen
Nectar/ pollen
Nectar/ pollen
Nectar/ pollen
predator
Habropoda bee
30 species of bees
Dasymutilla
predator
shelter
shelter
predator
predator
predator
predator
Metepiera spider
Wilsons warbler
Crab spider
Fringe-toed, leopard, brush
Phiddipus spider
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Science
1993-2000 Saul-Gershenz triungulins mimic bees
1895 Harrington large triungulins on bees
1956 McSwain describes larvae as Meloe sp. A
28 years
33 years
18 years
54 years
26 years
1928 Van Dyke describes adult Meloe franciscanus
from S.F
1841 Siebold recognizes phoretic relationship
1982 Pinto determines Meloe sp. A as M.
franciscanus
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Meloid History

• 1700, Goedart was the first to associate the
  triungulin larvae of Meloe with adults
• 1727 Frisch considered them to be lice and this
  error was perpetuated.
• 1767 Linnaeus in Systema Naturae gave the name
  Pediculus apis.
• 1828 Dufour described the genus Triungulinus for
  larvae of Meloe attached to an Andrena bee. Meloe
  triungulin claws in the form of a trident
  inspired Dufour to name his bee louse
  Triungulinus
• 1841 Seibold recognized the phoretic relationship
  between triungulin of Meloe bees.
• 1851 Newport definitely established that larvae
  of Meloe develop in the cells of bees
• 1857 and 1859 Fabre observed the feeding behavior
  of the triungulin larvae in bee nests and applied
  the term hypermetamorphosis.
• 1895 Harrington notes large numbers of
  triungulins on bees
• 1928 Van Dyke describes Meloe franciscanus adult
  from SF
• 1956 McSwain describes larvae,Meloe sp. A
• 1982 Pinto identifies Meloe sp. A larvae as Meloe
  franciscanus.

Adapted from Pinto Selander 1970
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Aggregation height vs. perching bee height

• Venereal transfer
• Bee bee contact

Count
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• Ecosystem Interactions

Kelso Dunes
Petalonyx
Grasses
Larrea
Perching
Perching
Eggs
Perching
Herbivore
Eggs
Nectar/ pollen
Nectar/ pollen
Nectar/ pollen
Nectar/ pollen
predator
30 species of bees
Habropoda bee
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Science
1993-2000 Saul-Gershenz triungulins mimic bees
1895 Harrington large triungulins on bees
1956 McSwain describes larvae as Meloe sp. A
28 years
33 years
18 years
54 years
26 years
1928 Van Dyke describes adult Meloe franciscanus
from S.F
1841 Siebold recognizes phoretic relationship
1982 Pinto determines Meloe sp. A as M.
franciscanus
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Adaptation for grasping
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Why aggregate?

• 1 Defense against predation-Distastfulness
  precedes gregariousness
• 2. Reduction of water loss - small insects
• 3. Start out aggregated due to the oviposition
  behavior of female, the eggs laid in large groups
• 4. Patchy resources, patchy environment

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Pheromones or Allomones

• Intra-specific bee-bee sexual atttractant
• Intra-specific triung-triung aggregation
• Interspecific triungulin-bee aggressive mimicry
• proportion
• concentration
• context

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Hypermetamorphosis

• in Meloe

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How to get to your dream house -patch leaving
mechanisms Hitchhiking is an iffy mode of
transport if your time is limited However, if
its a long way you might as well get a direct
flight or at least one with just a few stops and
bumps. And if your hitching a little cheesecake
goes a long way
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