Orius minutus
| Orius minutus | |
|---|---|
| |
| Orius minutus feeding on Trioza rhamni. | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hemiptera |
| Suborder: | Heteroptera |
| Family: | Anthocoridae |
| Genus: | Orius |
| Species: | O. minutus
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| Binomial name | |
| Orius minutus (Wolff, 1811)[1]
| |
Orius minutus is a Palearctic species of minute pirate bug in the family Anthocoridae.[1] O. minutus is naturally distributed throughout Europe, western Russia, North Africa, China, Japan, and Siberia[1][2] The predatory bug was accidentally introduction into North America through plant material commerce and regular dispersal; the introduction of O. minutus is generally considered beneficial to the agricultural industry.[1][3][4] O. minutus is an important addition to the predator complex of many crops, and its role as a non-commercialized biological control agent highlights its unique contribution to pest management strategies.[1][3][4]
Diagnostics
[edit]Adults
[edit]Adult females of O. minutus are larger (2.05-2.60 mm total length) and more broadly ovate (0.85-0.97 mm pronotal width) than males, who are slenderer (0.7-0.82 mm pronotal width) and possess thicker antennae.[1] The heads range from dark brown to black, all sporting yellow antennae.[1] The pronotum and scutellum are brownish-grey to brownish-black, with the hardened forewings yellowish brown.[1] The underside and hind legs are dark brown to black, with the front and middle legs yellow.[1] Lengths of golden setae adorn the dorsal side of the insect.[1]
Nymphs
[edit]Fifth instar nymphs of O. minutus are differentiated from other members of the genus Orius (e.g. O. tristicolor) by their broadly ovate body shape with one-third of the wing pad's tip a much darker colour than the rest of the dorsum.[1] The maximum width of the pronotum is 0.70 mm or greater.[1]
It is difficult to differentiate between earlier instars; many members of the genus Orius are a creamy white colour prior to their fifth instar.[1] However, O. minutus are generally more robust and broader than other species.[1] Their eyes nearly touch the anterior margin of the pronotum.[1] The head is relatively short, with the protunum almost 1.5 times the width of the head.[1]
Reproduction
[edit]Mating
[edit]O. minutus females are functionally monandrous.[5] Generally, females can not be inseminated by one mating;[5] only if the first mating fails will the females choose to mate with another male.[5] Females will refuse unwanted mating attempts by lifting their ovipositors and struggling;[5] such behaviours suggest females control the functional monandry.[5] The number of unique male partners does not affect fecundity, though mating with a single male decreases the hatching success of eggs.[5] Males are polygamous and can inseminate at least three females at a rate of one female per day;[5] the insemination ability of males persists for at least three copulations.[5]
Unlike many members of Anthocoridae, traumatic insemination does not occur within O. minutus.[6] Males instead employ extragenital insemination to transfer spermatozoa into the female's body.[6] The male's needle-like flagellum is inserted intersegmentally between the female's abdominal segments without wounding or scarring her outer body;[6] the cone present on male genitalia assists in expanding the space between the female's lower abdominal segments.[6] Males possess a partially sclerotized copulatory tube to support and guide the flagellum into the female's sperm pouch.[6] The spermatozoa can remain within the sperm pouch weeks after depositing several eggs, suggesting the sperm pouch functions as a long-term storage organ.[6] Females may be able to store spermatozoa for their entire lifetime, a consequence of functional monandry.[6] An extragenital structure called the ectospermalege is located at the fourth segment of the female body.[6] Underneath the ectospermalege is the mesospermalege, a special endodermal pouch that receives the spermatozoa.[6] O. minutus females lack spermatheca, instead possessing a pair of pseudospermatheca at the base of their lateral oviducts;[6] the pseudospermatheca receives the spermatozoa, which transfers from the mesospermalege in the hemolymph.[6]
Pheromones
[edit]Contact sex pheromones are present within the trails of O. minutus.[7] Trails left by mature virgin females aid males in locating a mate.[7] Males will linger on leaves exposed to trails left by mature virgin females, allowing males to locate conspecific females who had recently deposited trails on the plant.[7] Males will respond to the trails regardless of their mating experience, though only trails from mature females arrest males.[7] Females respond with weak arrestment to the leaves walked on by males, which could further assist in finding a mate.[7]
Effect of temperature
[edit]Although O. minutus have a higher rate of reproduction at temperatures between 17 and 26 °C, they experience a decrease in lifetime fecundity at and above temperatures of 26 °C;[8] the reduction in fecundity at higher temperatures suggests that O. minutus are disadvantaged when experiencing wide ranges of temperatures.[4]
Life history
[edit]O. minutus females overwinter fertilized, usually emerging from hibernation in the early spring.[1][8][9] Males can hibernate but are unlikely to survive the winter due to their lack of diapause and inadequate lipid accumulation.[1][10] Shortly after hibernation ends, eggs are deposited onto the base of developing flower buds or the midrib on the bottom of leaves.[1][11]
O. minutus has five nymphal instars.[1] The developmental time from egg to adult depends on temperature and location, though adulthood is generally reached within 24 to 30 days.[1][9] O. minutus produce at least two generations annually, though up to four generations can be produced under ideal conditions.[1][9] Adults collected from early spring and mid-autumn suggest O. minutus is bivoltine.[1][9]
Diet
[edit]O. minutus are generalist predators of small insects, including aphids, mites, thrips, whiteflies and scales.[1][3] Though chiefly predacious, O. minutus may occasionally feed on plant material and sap (e.g. the fluid produced by Eryngium campestre).[1]
Behaviour
[edit]Foraging and flying
[edit]Though O. minutus initially flies out in random directions, the discovery of prey patches shifts their dispersal into foraging activity;[2] individuals that discover patches with a high prey density are hesitant to fly out from the patches.[2] Abiotic factors significantly influence this behaviour, with increased plant foraging behaviours correlating with high solar radiation and low humidity.[2] Both males and females are diurnal fliers, though females engage in less flight activity than males.[2]
Diapause
[edit]The critical photoperiod for inducing diapause is between 14.5-9.5D and 15L-9D at 22 °C, corresponding to late summer in many regions occupied by O. minutus.[10] During diapause, the insects do not copulate, and the female's ovaries remain small until the following spring.[10] Adult females do not enter diapause regardless of short day length if their nymphal stages were spent under long day length.[10] Adult diapause is not induced in males due to a shortage of lipid accumulation.[10]
References
[edit]- ^ a b c d e f g h i j k l m n o p q r s t u v w x y Lattin, J.D.; Asquith, A. (1989). "Orius minutus (Linnaeus) in North America (Hemiptera: Heteroptera: Anthocoridae)". Journal of the New York Entomological Society. 97 (4): 409–416. JSTOR 25009791.
- ^ a b c d e Tuda, M.; Shima, K. (2002). "Relative importance of weather and density dependence on the dispersal and on-plant activity of the predator Orius minutus". Popular Ecology. 44 (3): 251–257. Bibcode:2002PopEc..44..251T. doi:10.1007/s101440200028.
- ^ a b c Rahman, M.A.; Sarker, S.; Ham, E.; Lee, J.S.; Lim, U.T. (2022). "Prey preference of Orius minutus and its functional response in comparison that of O. laevigatus, on Tetranychus urticae". Journal of Asia-Pacific Entomology. 25 (2): 101912. Bibcode:2022JAsPE..2501912R. doi:10.1016/j.aspen.2022.101912.
- ^ a b c Lan, R.; Ren, X.; Cao, K.; Zhou, X.; Jin, L. (2022). "Demographic evaluation of the control potential of Orius minutus (Hemiptera: Anthocoridae) preying on Dendrothrips minowai Priesner (Thysanoptera: Thripidae) at different temperatures". Insects. 13 (12): 1158. doi:10.3390/insects13121158. PMC 9785448. PMID 36555068.
- ^ a b c d e f g h Arakawa, T.; Taniai, K.; Maeda, T. (2019). "The mating systems of three species of minute piratebug, Orius sauteri, O. minutus, and O. strigicollis". The Netherlands Entomological Society. 167 (2): 141–151. Bibcode:2019EEApp.167..141A. doi:10.1111/eea.12740.
- ^ a b c d e f g h i j k Taniai, K.; Arakawa, T.; Maeda, T. (2018). "Traumatic insemination is not the case in three Orius species (Heteroptera: Anthocoridae)". PLOS ONE. 13 (12): e0206225. Bibcode:2018PLoSO..1306225T. doi:10.1371/journal.pone.0206225. PMC 6281218. PMID 30517107.
- ^ a b c d e Maeda, T.; Fujiwara-Tsuji, N.; Yasui, H.; Matsuyama, S. (2016). "Female sex pheromone in trails of the minute pirate bug, Orius minutus (L)". Journal of Chemical Ecology. 442 (5): 433–443. Bibcode:2016JCEco..42..433M. doi:10.1007/s10886-016-0702-2. PMID 27184908.
- ^ a b Kakimoto, K.; Urano, S.; Noda, T.; Matuo, L.; Sakamaki, Y.; Tsuda, K.; Kusigemati, K. (2005). "Comparison of the reproductive potential of three Orius species, O.strigicollis, O. sauteri, and O. minutus (Heteroptera : Anthocoridae), using eggs of the Mediterranean flour moth as a food source". Applied Entomology and Zoology. 40 (2): 247–255. Bibcode:2005AppEZ..40..247K. doi:10.1303/aez.2005.247.
- ^ a b c d Collyer, E. (1953). "Biology of some predatory insects and mites associated with the fruit tree red spider mite (Metatetranychus ulmi (Koch)) in south-eastern England. II. Some important predators of the mite". Journal of Horticultural Science. 28: 85–97. doi:10.1080/00221589.1953.11513772.
- ^ a b c d e Ito, K.; Nakata, Y. (1998). "Diapause and survival in winter in two species of predatory bugs, Orius sauteri and Orius minutus". Entomologia Experimentalis et Applicata. 89: 271–276. doi:10.1046/j.1570-7458.1998.00408.x.
- ^ Fulmek, L. (1930). "Kenntnis der entwicklungsstadien von Triphleps minuta L. (Anthocoridae, Hemiptera, Heteroptera)". Insektenbiol. 25: 82–88.