Intraguild predation between two lady beetle predators is more sensitive to density than species of extraguild prey
- PDF / 532,389 Bytes
- 13 Pages / 547.087 x 737.008 pts Page_size
- 34 Downloads / 223 Views
(0123456789().,-volV) ( 01234567 89().,-volV)
Intraguild predation between two lady beetle predators is more sensitive to density than species of extraguild prey Fateme Ranjbar . J. P. Michaud . M. Amin Jalali
. Mahdi Ziaaddini
Received: 6 March 2020 / Accepted: 20 July 2020 International Organization for Biological Control (IOBC) 2020
Abstract Oenopia conglobata (Linnaeus) and Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae) are important predators of the pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), a key pest of pistachio. The abundance of M. sexmaculatus has recently increased in pistachio orchards, while that of O. conglobata has declined. We designed laboratory experiments to (1) evaluate the potential for intraguild predation (IGP) between these two species, (2) detect any possible asymmetries in IGP interactions, and (3) characterize the sensitivity of IGP to varying densities of two extraguild (EG) prey, A. pistaciae and Aphis gossypii Glover (Hemiptera: Aphididae). We measured rates of IGP by fourth instar larvae and female adults (both starved for 12 h) on vulnerable immature
life stages of the other species (eggs, first, and second instar larvae). IG and EG prey consumption were tallied after 12 h. All factors influenced rates of IGP, but species of IG predator, and life stage and density of EG prey, contributed the most variance. IGP decreased parabolically with increasing prey densities. IGP on eggs was higher than on first instars, which was higher than on second instars, suggesting palatability declined in later life stages. The larger M. sexmaculatus exhibited higher voracity than the smaller O. conglobata in both predation and IGP. Both species consumed more A. pistaciae than A. gossypii in all treatments, which may reflect either lower handling time or lower food value per prey. Keyword Agonoscena pistaciae Aphis gossypii Menochilus sexmaculatus Oenopia conglobata Pistacia vera
Handling Editor: Dirk Babendreier F. Ranjbar M. A. Jalali (&) M. Ziaaddini Vali-E-Asr University of Rafsanjan, Rafsanjan, Iran e-mail: [email protected] F. Ranjbar e-mail: [email protected] M. Ziaaddini e-mail: [email protected] J. P. Michaud Department of Entomology, Kansas State University, Agricultural Research Center-Hays, Hays, KS, USA e-mail: [email protected]
Introduction Pistachio, Pistacia vera L. (Anacardiaceae), is an important crop in Iran where it is source of valuable export income. It is cultivated primarily in regions with challenging growing conditions—cold winters, hot summers, high salinity, low soil quality, and low average annual rainfall (ca. 100 mm). Furthermore, monocultures of pistachio trees have created a system
123
F. Ranjbar et al.
with relatively low plant diversity, which has exacerbated some pest problems (Mehrnejad 2001). The common pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), is a key pest of cultivated pistachio trees in Iran and many other countries (Burckhard
Data Loading...
