Figures
Fig. 1: Antenna (inset: III. and IV. antennal segment)
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Fore- and hindwing, base of fore wing with alula
Fig. 6: Sternites V and VI
Fig. 7: Tergites V - VII
Fig. 8: Tergites VIII and IX
ITS-RFLP gel patterns (1&8 ladder, 2 PCR-product, 3 RSAI, 4 HaeIII, 5 MspI, 6 HinfI, 7 AluI)
Fig. 9: Primer pair P1/28Z
Taxonomic Information
Species:
Thrips imaginis Bagnall, 1926
Synonyms:
Aptinothrips apertus Kelly & Mayne, 1934
Neophysopus aureolus Girault, 1928
Neophysopus io Girault, 1927
Thrips shakespearei Girault, 1927
Thrips apicalis Bagnall, 1926
Thrips fortis Bagnall, 1926
Thrips imaginis Bagnall, 1926
Common name:
Apple blossom
Plague thrips
Present taxonomic position:
Family: Thripidae Stephens, 1829
Subfamily: Thripinae (Stephens) Karny, 1921
Genus: Thrips Linneaeus, 1758
Species Recognition
General information about the genus Thrips:There are about 280 species currently recognized in the genus Thrips making this genus one of the largest groups within the Thysanoptera. They are separated from other genera in having the following characters, antenna comprising 7 or 8 segments with segments III and IV containing forked sense cones, the head has two pairs of ocellar setae (II and III), pair I is missing, the pronotum with four long setae on the posterior margin, forewing 1st vein usually has a row of setae interrupted by gaps, on lateral sides of abdominal tergites V to VIII there are paired ctenidia, abdominal tergite VIII with ctenidia posterior to the spiracles.
Typical character states of Thrips imaginis:
Body color
Mainly brown or mainly pale or yellow, with some darker markings
Antennae
Number of antennal segments: 7
Segment IV - forked sensorium: scarcely extending beyond base of segment V
Segments II and III shape: more or less symmetric
Segments III & IV sensoria: emergent and forked
Base of sensorium on antennal segment VI: no more than 2 times as wide as base of nearest seta
Terminal antennal segments: rarely elongate
Head:
Distance between bases of ocellar setae III: greater than width of first ocellus
Head shape between compound eyes: not prolonged
Ocellar setae III on head: arising on anterior margin of, or in front of, ocellar triangle
Postocular setae I: absent
Surface of head, pronotum and fore legs: without strong reticulate sculpture
Ocellar setae I in front of anterior ocellus: absent
Prothorax
Number of pairs of elongate pronotal setae: 0-3
Number of pairs of elongate posteroangular pronotal setae: 2
Pronotum shape: rectangular
Number of pairs of pronotum posteromarginal minor setae: 5-6
Number of pairs of pronotum anteromarginal minor setae: 4-5
Mesothorax
Mesothoracic endofurca: with median spinula
Metathorax
Metanotal median area sculptured lines: transverse at anterior, but with irregular equiangular reticulation near posterior
Metanotal median setae length: longer than lateral metanotal setae
Metanotal median setae position: arising behind anterior margin
Metanotum: without campaniform sensilla
Metanotum major sclerite: with two major sclerites, metascutum and metascutellum
Metanotum median area: with at least some equiangular reticulation
Metanotum sculpture: without dominant sculptured triangle medially
Metathoracic endofurca: transverse, sometimes with simple median spinula
Wings
Wings: present and more than half as long as abdomen
First vein of forewing: distinct from costal vein
Forewing anterior margin: with setae and cilia but cilia longer than setae
Forewing clavus: terminal veinal seta longer than subterminal seta
Forewing color: uniformly pale or weakly shaded
Forewing costal fringe of cilia: arising at anterior margin of wing
Forewing costal setae at middle of wing: shorter than median width of wing
Forewing first vein setal row: incomplete, with setae not closely and uniformly spaced
Forewing posterior margin cilia: undulated near apex
Forewing second vein setal row: complete, with setae closely and uniformly spaced
Forewing surface: not reticulate
Forewings: with veins, setae and microtrichia
Legs
Fore tarsus inner apex: without tooth
Fore tibial apex: not extending around fore tarsus - with small curved claw ventrolaterally
Mid and hind tarsi: with two segments
Abdomen:
Pleurotergal discal setae: present
Abdominal pleurotergites: not covered in microtrichia
Abdominal segment X: never tubular, longitudinally incomplete ventrally in both sexes
Abdominal sternite II: with 1 or 2 discal setae in addition to marginal setae or with marginal setae but no discal setae
Abdominal sternite III of female: without glandular areas
Abdominal sternite VII: with discal setae present on median area
Abdominal sternite VII median marginal setae: arising at margin or in front of margin
Abdominal sternites IV , V and VI: with discal setae present medially as well as marginal setae
Number of lateral marginal setae on abdominal tergite II: 3
Abdominal tergites: without curved wing-retaining setae
Abdominal tergites IV & V median setal pair: much shorter than distance between their bases
Abdominal tergites V-VII: with pair of ctenidia laterally
Number of discal setae on sternite V: 14-20
Setae on abdominal tergite X: slender
Surface of lateral thirds of abdominal tergites: without regular rows of fine microtrichia
Ctenidia on tergite VIII: posteromesad to spiracle
Tergite VIII posteromarginal comb of microtrichia: present laterally, incomplete medially
Tergite VIII posteromarginal microtrichia: long, slender and irregular
Biology
Life history:
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle can take about 15 days (Lewis, 1973) to over a month and adults may live for more than one month producing several generations in one year depending on seasonal weather. With greenhouse temperatures the developmental time from egg to adult can decrease to about one week.
Host plants:
Polyphagous
Vector capacity:
None identified
Current known distribution:
Australia, New Zealand
Additional notes:
This species is known as the ‘plague thrips’ throughout Australia where it is found to breed and feed in the flowers of many native plant species.
Bibliography
Bailey, SF (1957): The thrips of
California Part I: Suborder Terebrantia. Bulletin of the California Insect
Survey 4, no. 5: 143-220.
Andrewartha, HG (1935) The prediction and control of outbreaks of Thrips imaginis. BAGNALL., J. austral. Inst. agric. Sci. 1: 78-80.
Andrewartha, HG (1936): Thrips investigation - 8. The influence of temperature on the rate of development of the immature stages of Thrips imaginis BAGNALL and Haplothrips victoriensis BAGNALL. J. Council Scient. Industr. Res., 9, 57-64.
Bailey, SF (1957): The thrips of California Part I: Suborder Terebrantia. Bulletin of the California Insect Survey 4, no. 5: 143-220.
Davidson, J & Andrewartha, HG (1948): The influence of rainfall, evaporation and atmospheric temperature on fluctuations in the size of a natural population of Thrips imaginis (Thys.). J. Anim. Ecol., 17, 200-222.
Davidson, J & Andrewartha, HG (1948): Annual Trends in a Natural Population of Thrips imaginis (Thysanoptera). Journal of Animal Ecology, 17, 193-199.
Evans, JW (1932): The bionomics and economic importance of Thrips imaginis Bagnall with special reference to the effect on apple production in Australia. Pamph. Coun. scient. ind. Research Australia, 30.
Greber, RS, Klose, MJ, Milne, JR & Teakle, DS (1991): Transmission of Prunus Necrotic Ringspot Virus using plum pollen and thrips. Annals of Applied Biology, 118, 589-593.
Kirk, WDJ (1984): Ecological-Studies on Thrips-Imaginis Bagnall (Thysanoptera) in Flowers of Echium-Plantagineum L in Australia. Australian Journal of Ecology, 9, 9-18.
Kirk, WDJ (1987): Effects of Trap Size and Scent on Catches of Thrips-Imaginis Bagnall (Thysanoptera, Thripidae). Journal of the Australian Entomological Society, 26, 299-302.
Lewis, T (1973): Thrips their biology, ecology and economic importance. Academic Press Inc., London Ltd. 349 pp.
Milne, JR, Milne, M & Walter, GH (1997): A key to larval thrips (Thysanoptera) from granite belt stonefruit trees and a first description of Pseudanaphothrips achaetus (Bagnall) larvae. Australian Journal of Entomology, 36, 319-326.
Milne, JR & Walter, GH (2003): The coincidence of thrips and dispersed pollen in PNRSV-infected stonefruit orchards - a precondition for thrips-mediated transmission via infected pollen. Annals of Applied Biology, 142, 291-298.
Moritz G, Morris DC, Mound LA (2001): ThripsID - Pest thrips of the world. ACIAR and CSIRO Publishing Collingwood, Victoria, Australia, CDROM ISBN 1 86320 296 X.
Moritz G, Mound LA, Morris DC, Goldarazena A (2004): Pest thrips of the world - an identification and information system using molecular and microscopial methods. CBIT, University of Queensland,CDROM ISBN 1-86499-781-8.
Mound, LA & Kibby, G (1998): Thysanoptera: An identification guide, (2nd edition). CAB International, Wallingford and New York, 70pp.
Mound, LA & Marullo, R (1996): The thrips of Central and South America: An Introduction (Insecta: Thysanoptera). Associated Publishers, Gainesville.
Mound, LA & Masumoto, M (2005): The genus Thrips (Thysanoptera, Thripidae) in Australia, New Caledonia and New Zealand. Zootaxa, 3-64.
Nakahara, S (1985): Review of Thrips hawaiiensis and revalidation of T. florum (Thysanoptera: Thrpidae). Proceedings of the Entomological Society of Washington, 87:864-870.
Nakahara, S (1994): The Genus Thrips Linnaeus (Thysanoptera: Thripidae) of the New World. USDA Agricultural Research Service Technical bulletin No. 1822.
Shao, R & Barker, SC (2003): The highly rearranged mitochondrial genome of the Plague Thrips, Thrips imaginis (Insecta: Thysanoptera): Convergence of two novel gene boundaries and an extraordinary arrangement of rRNA genes. Mol. Biol. Evol., 20, 362-370.
Stannard, LJ (1968): The thrips, or Thysanoptera, of Illinois. Illinois Natural History Survey Bulletin 29: 215-552.
Steiner, MY & Goodwin, S (2005): Management of thrips (Thysanoptera : Thripidae) in Australian strawberry crops: within-plant distribution characteristics and action thresholds. Australian Journal of Entomology, 44, 175-185.
Teulon, DAJ, Penman, DR & Ramakers, PMJ (1993): Volatile chemicals for thrips (Thysanoptera, Thripidae) host-finding and applications for thrips pest-management. Journal of Economic Entomology, 86, 1405-1415.
Wilson, LJ & Bauer, LR (1993): Species composition and seasonal abundance of thrips (Thysanoptera) on cotton in the Namoi Valley. Journal of the Australian Entomological Society, 32, 187-192.
Wilson, LJ, Bauer, LR & Walter, GH (1996): 'Phytophagous' thrips are facultative predators of two spotted spider mites (Acari: Tetranychidae) on cotton in Australia. Bulletin of Entomological Research, 86, 297-305.
Links:
Mound, LA (2005): Thysanoptera (Thrips) of the World
- A Checklist. http://www.ento.csiro.au/thysanoptera/worldthrips.html