Understanding Species Implications for IPM. Malaria causes around 1.3 million deaths a year...

Understanding SpeciesUnderstanding SpeciesImplications for IPMImplications for IPM

Malaria causes around 1.3 million deaths a Malaria causes around 1.3 million deaths a year worldwideyear worldwide

Control of malaria heavily relies on control Control of malaria heavily relies on control of its vector of its vector Anopheles maculipennisAnopheles maculipennis

What was thought to beWhat was thought to be A. maculipennis A. maculipennis was actually a complex of 7 specieswas actually a complex of 7 species

Different species of Different species of mosquitoes differ in their mosquitoes differ in their

ability to carry ability to carry

PlasmodiumPlasmodium

Presence of Presence of AnophelesAnopheles but not but not malaria mystery solved!malaria mystery solved!

Cryptic or Sibling SpeciesCryptic or Sibling Species

Cryptic or Sibling SpeciesCryptic or Sibling Species• Species that are virtually identical in Species that are virtually identical in

their morphologytheir morphology

Nilapavarta(Homoptera: Delphacidae)

Weed grass(Leersia hexandra)

Rice(Oryza sativa)

• Widespread in natureWidespread in nature

Cryptic or Sibling SpeciesCryptic or Sibling Species

• Present among insects of economic Present among insects of economic importanceimportance

Cryptic or Sibling SpeciesCryptic or Sibling Species

Bactrocera(Diptera: Tephritidae)

Oncopsis(Homoptera: Cicadellidae)

• Usually associated with different plant or Usually associated with different plant or host specieshost species

Cryptic or Sibling SpeciesCryptic or Sibling Species

Archips(Lepidoptera: Tortricidae)

ID of species on morphological grounds is ID of species on morphological grounds is often not good enoughoften not good enough

What initially seems to be a single poly or What initially seems to be a single poly or oligophagous species could represent a oligophagous species could represent a

collection of cryptic species collection of cryptic species

Nilapavarta(Homoptera: Delphacidae)

Weed grass(Leersia hexandra)

Rice(Oryza sativa)

What initially seems to be a single poly or What initially seems to be a single poly or oligophagous species could represent a oligophagous species could represent a

collection of cryptic species collection of cryptic species

Nilapavarta(Homoptera: Delphacidae)

Weed grass(Leersia hexandra)

Rice(Oryza sativa)

Aonidiella auranti(Homoptera: Margarodidae)

Correct identification of organisms is essential for Correct identification of organisms is essential for any intelligent interpretation of biological controlany intelligent interpretation of biological control

California

Red scale

Aonidiella auranti(Homoptera: Margarodidae)

Chrysomphalus

The red scale was originally classified in the The red scale was originally classified in the wrong genuswrong genus

The red and yellow scale insects were not The red and yellow scale insects were not separated taxonomically until 1937separated taxonomically until 1937

Aonidiella aurantii

Parasitoids of the yellow scale were introduced in Parasitoids of the yellow scale were introduced in California to control the red scale failing to California to control the red scale failing to

establishestablish

Aonidiella aurantii

China

California

Parasitoids of the yellow scale were introduced to Parasitoids of the yellow scale were introduced to California to control the red scale failing to California to control the red scale failing to

establishestablish

Aonidiella aurantii

China

California

It was concluded that no parasitoids to It was concluded that no parasitoids to control the red scale existed in Asiacontrol the red scale existed in Asia

Since 1880 an aphelinid parasitoid had been Since 1880 an aphelinid parasitoid had been known to attack red scale insectsknown to attack red scale insects

Red scale(Homoptera: Margarodidae)

California

Aphytis chrysomphali(Hymenoptera: Aphelinidae)

Compere found in China that the red scale insect Compere found in China that the red scale insect was kept at low densities by an was kept at low densities by an AphytisAphytis species species

ChinaGeorge CompereAphytis lingnanensis

(Hymenoptera: Aphelinidae)

The The AphytisAphytis species found by Compere was species found by Compere was identified as identified as Aphytis mytilaspidisAphytis mytilaspidis

George CompereAphytis lingnanensis

(Hymenoptera: Aphelinidae)

Aphytis mytilaspidis

Aphytis mytilaspidis

China

George CompereAphytis lingnanensis

(Hymenoptera: Aphelinidae)

Aphytis mytilaspidisCalifornia

Aphytis mytilaspidisAphytis mytilaspidis was already present in was already present in CaliforniaCalifornia

Aphyitis mytilaspidisAphyitis mytilaspidis does not attack red scale does not attack red scale insects in Californiainsects in California

George CompereAphytis lingnanensis

(Hymenoptera: Aphelinidae)

Aphytis mytilaspidisCalifornia

George CompereAphytis chrysomphali

(Hymenoptera: Aphelinidae)

Aphytis mytilaspidisCalifornia

Aphytis chrysomphaliAphytis chrysomphali, also present in California, , also present in California, was also erroneously named was also erroneously named A. mytilaspidisA. mytilaspidis

George CompereAphytis chrysomphali

(Hymenoptera: Aphelinidae)

Aphytis mytilaspidisCalifornia

Thus, it was erroneously concluded that the Thus, it was erroneously concluded that the parasitoid found in China controlling the red parasitoid found in China controlling the red

scale was already present in California scale was already present in California

• The 50 year failure of red scale insect control The 50 year failure of red scale insect control was based on a series of misidentifications.was based on a series of misidentifications.

• Searches made in SouthSearches made in South America instead of in Asia.America instead of in Asia.

• Introduction of unsuitable Introduction of unsuitable parasitoids.parasitoids.

• Failure to introduce the right parasitoid Failure to introduce the right parasitoid because it was misidentified as already present because it was misidentified as already present in California.in California.

The Red Scale Insect Control in The Red Scale Insect Control in CaliforniaCalifornia

• One of the best examples of a long term One of the best examples of a long term failure turned into a success by the failure turned into a success by the eventual introduction of appropriate eventual introduction of appropriate natural enemies.natural enemies.

• Illustrates the need to understand the Illustrates the need to understand the limits of cryptic species.limits of cryptic species.

Aphytis lingnanensis(Hymenoptera: Aphelinidae)

Can we predict where to expect cryptic Can we predict where to expect cryptic species to occur?species to occur?

Different activity cyclesDifferent activity cycles

4-5 weeks

Nocturnal

Diurnal

Specific mate recognition keeps species Specific mate recognition keeps species reproductively isolatedreproductively isolated

Some organisms recognize each other through tactiletactile or sonic clues

Coccophagus spp.

Others recognize each other through Others recognize each other through complex mating behaviorscomplex mating behaviors

If non visual ways of mate recognition are presentIf non visual ways of mate recognition are present

Exceptionally generalized habits or Exceptionally generalized habits or ecologies ?ecologies ?

Biological differences across spaceBiological differences across space

Biological differences across spaceBiological differences across space

So how can we tell?

= ?

Experimental approaches:Experimental approaches:

Behavioral observations in natureBehavioral observations in nature

b

Experimental approaches:Experimental approaches:

Cross-mating experimentsCross-mating experiments

x x

x

xa a

ab

a bb

Control ControlExperiment

a b

CAUTION!

CAUTION!

AllozymesAllozymes

&&

DNADNA

Molecular genetics techniquesMolecular genetics techniques

• Use as markers when limits Use as markers when limits have been defined by other have been defined by other means.means.

• Use to measure differences in allele Use to measure differences in allele frequencies to establish differentiation.frequencies to establish differentiation.

CytogeneticsCytogenetics

Polytene Chromosome

Analysis of mating signal structure and Analysis of mating signal structure and functionfunction

Cryptic Species Pose a Problem for Cryptic Species Pose a Problem for IPMIPM

• In assessments of:In assessments of:

- - Pest statusPest status

- Biocontrol potential- Biocontrol potential

- Host specificity- Host specificity

Cryptic Species Pose a Problem for Cryptic Species Pose a Problem for IPMIPM

• In assessments of:In assessments of:

- - Geographic distributionGeographic distribution

- Activity cycles- Activity cycles

- Pesticide resistance- Pesticide resistance