Quantification of consumption of corn pollen by the predator Coleomegilla maculata (Coleoptera: Coccinellidae) during anthesis in an Illinois cornfield

Abstract

1 Coleomegilla maculata DeGeer feeds on corn pollen in the field, but the degree to which this predator relies on corn pollen as part of its diet is not well understood. We quantified the amount of pollen consumed by C. maculata second, third and fourth instars and adults in the field. 2 Laboratory experiments were conducted to determine the digestion rate and duration of different stadia or stages using temperature regimens that reflected field conditions during anthesis. Coleomegilla maculata larvae and adults were collected from the field and the amount of pollen in their digestive tracts was determined gravimetrically. The rate of digestion, duration of each life stage and the field observations were used to estimate the amount of pollen consumed by second, third and fourth instars and adults. 3 Our models estimate that larvae consume 0.66, 1.67 and 3.30 mg of pollen during the second, third and fourth stadia, respectively. Adults consumed an estimated 13.15 mg during anthesis. 4 The relevance of our results to ecological risk assessment of transgenic insecticidal corn and predator life history strategies is discussed. The results presented here are a first attempt to quantify pollen consumption by a predator, and future areas of research are suggested.

Morphological characterization of pollens from three Apiaceae species and their ingestion by twelve-spotted lady beetle (Coleoptera: Coccinellidae)

“…This result corroborates those of Smith (1965) and Lundgren et al (2005), who observed that larvae of C. maculata also ingest pollen grains, not only the adults. This result also indicates that this lady beetle species accepted the pollen grains of the three species as food, however, more studies are needed to conclude if this food is adequate to guarantee its survival and reproduction, preferentially leading to longer lifespan of adults and fecundity, or whether it is simply a complementary food source that would only warrant its survival, as was pointed out by Almeida and Ribeiro-Costa (2009).…”

“…However, Lundgren et al (2005) estimated that the consumption of corn pollen grains (Z. mays) by fourth instar larvae of C. maculata was of 3.30 mg and the adults consumed 13.15 mg of pollen of this Poaceae during the period of anthesis in transgenic corn crops in Illinois, USA, without mentioning what this represents in terms of the number of ingested pollen grains. Dupuis et al (1987) estimated that 2500 Z. mays pollen grains in one milligram, therefore, considering only the consumption of fourth instar larvae and of adults of C. maculata recorded by Lundgren et al (2005), would give a total of 41125 pollen grains. Therefore, it gives a quantity relatively higher than the consumption of Apiaceae grains by these phases in the present study, reaching a peak of 14.94% greater than the dill grains.…”

“…Coleomegilla maculata has a polyphagous feeding habits and is normally present in agro-ecosystems, including Brazil, where it develops and reproduces itself well when feeding on aphids alone, or even on eggs and neonate larvae of Lepidoptera and Coleoptera (Patt et al, 1997a;Harmon et al, 2000;Lundgren et al, 2005;Lixa et al, 2010).…”

“…The ingestion of corn pollen grains (Zea mays L., Poaceae) by larvae and adult C. maculata has been recorded, and whose mean average protein content was estimated at 24% (Roulston et al, 2000), making up quite an attractive botanical species for this coccinellid (Smith, 1965;Lundgren et al, 2005;Weber and Lundgren, 2011). Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera: Coccinelidae) adults collected in organic vegetable crops were also determined as being able to ingest pollen grains from ten botanical families, including Apiaceae, although their species were not identified (Medeiros et al, 2010).…”

Effects of Food Deprivation on the Development of Coleomegilla maculata (De Geer) (Coleoptera: Coccinellidae)

“…It is a natural enemy of aphids, mites, and eggs and larvae of coleopterans and lepidopterans (Hodek 1973, Weeden et al 2007, and also feeds on pollen and nectar to survive periods when prey is scarce (Hodek & Honek 1996, Lundgren et al 2004.…”