Abundance and stability of populations of chewing lice (Phthiraptera: Amblycera and Ischnocera) infesting two species of woodpeckers (Aves: Piciformes: Picidae)

Abstract

The annual abundance of chewing lice (Phthiraptera) was recorded from 1996 to 2015 in Manitoba, Canada, on two species of woodpeckers (Piciformes: Picidae). Yellow-bellied sapsuckers (Sphyrapicus varius (Linnaeus)) were infested with Menacanthus pici (Denny) (Amblycera: Menoponidae) and Penenirmus auritus (Scopoli) (Ischnocera: Philopteridae); northern flickers (Colaptes auratus (Linnaeus)) were also infested with M. pici, as well as two other Ischnocera, Penenirmus jungens (Kellogg) and Picicola porisma Dalgleish. The mean annual abundance varied from nine to 51 lice per bird for the four species, with prevalence, mean intensity, sex ratio, and nymphs per female also varying among louse species. Menacanthus pici populations on both hosts were unstable: abundance rose over two decades because of increasing prevalence, whereas the abundance of the other three louse species fluctuated around a mean. Population variability was similar for the lice on both hosts, with the metric, PV, ranging from 0.41 to 0.51 on a 0–1 scale, once the effect of the trend in abundance for M. pici had been removed. Although the population dynamics for species of lice on these two woodpeckers were distinct, inter-specific differences in population stability were less pronounced than observed in the few other species of bird lice studied in this way.

Stability of chewing louse (Phthiraptera: Amblycera and Ischnocera) populations infesting great horned owls (Aves: Strigidae)

“…The lowest previously observed values of PV for mean intensity were 0.3 for two species of lice on feral pigeons (Galloway and Lamb 2014), which suggests that temporal variation for mean intensity of lice on great horned owls is, in fact, remarkably low. Values of PV for louse prevalence on great horned owls at 0.21 and 0.34 were close to the average (0.28) of those observed for bird lice in Manitoba Lamb 2014, 2015b;Lamb and Galloway 2018).…”

“…In previous studies, lice on the same host showed speciesspecific PV and species with high abundance tended to have lower PV than less abundant species. As observed previously for chewing lice Lamb 2014, 2015b;Lamb and Galloway 2018), most of the temporal variation in louse abundance on great horned owls was accounted for by mean intensity rather than prevalence. Kurodaia magna and S. oculatus did show speciesspecific differences in PV for some population parameters, particularly prevalence and sex ratio, but were more similar than previously studied lice within multispecies louse communities on the same host.…”

“…Mean annual abundances for two species of lice infesting great horned owls were the highest recorded among 12 species of lice studied in Manitoba Lamb 2014, 2015b;Lamb and Galloway 2018), as expected given the large body size of their host (Rózsa 1997;Galloway and Lamb 2017;Lamb and Galloway 2019). Unexpectedly, the temporal variabilities for K. magna and S. oculatus were similar and high.…”

“…Studies of chewing lice (Phthiraptera: Amblycera, Ischnocera) on feral pigeons (Columba livia Gmelin, Aves: Columbidae) and woodpeckers (Aves: Picidae) have shown species-specific levels of average abundance and also specific levels of stability in their population parameters, even when different species inhabit the same host, subject to the same year-to-year fluctuations in environmental conditions (Galloway and Lamb 2014;Lamb and Galloway 2018). The 10 species studied so far have relatively stable populations, measured as temporal population variability (PV, Heath 2006), with PV = 0.51 ± 0.03 (standard error) on a scale of 0-1 Lamb 2014, 2015b;Lamb and Galloway 2018). In comparison, populations of other taxa of insects exhibit higher levels of temporal PV: aphids (Hemiptera: Aphididae) -0.70 ± 0.05, n = 5 (Lamb and MacKay 2010;Lamb et al 2011Lamb et al , 2012; beetles (Coleoptera) -0.64 ± 0.03, n = 14 (Lamb and Boivin 2017a;; and flies (Diptera) -0.57 ± 0.04 Boivin 2017a, 2017b).…”

Stability of native and exotic lady beetle populations in a diverse landscape

“…, Lamb et al. , Galloway and Lamb , Lamb and Boivin , b, Lamb and Galloway ). Many species have now been shown to exhibit characteristic density‐dependent processes that could lead to species‐specific levels of stability in the face of similar environmental variation (insects, Alyokhin et al.…”