A Comparison of Fitness Characters of Two Host Plant-Based Congeneric Species of the Banana Aphid,Pentalonia NigronervosaandP. Caladii

Abstract

Aphids and other phytophagous insects often show intra-specific variations in relation to host plant utilization. In several instances, intra-species variations lead to host-plant specialization. These are considered to be important source of speciation. In a recent study (Foottit RG et al. 2010. Zootaxa 2358: 25–38) two forms of the banana aphid, Pentalonia nigronervosa f typica Coquerel (Hemiptera: Aphididae) from banana hosts and P. nigronervosa f. caladii van der Goot collected from Zingiberaceae and Araceae respectively were described as separate species, P. nigronervosa Coquerel and P. caladii van der Goot, based on morphological and molecular differences. A study was undertaken to examine the ecological and biological characters in asexual wingless morphs of the two forms of P. nigronervosa sensu lat. using taro (Araceae) and banana (Musaceae) as host plants. The results showed consistent differences between the two forms. In biological characters, the apterous morphs off. caladii from taro host plants were found to be significantly more fecund, showed a higher net reproductive rate, longer reproductive duration, and their adults lived longer than the f. typica aphids from banana host plants. In ecological characters, f. caladii aphids formed bigger colonies and in significantly less time on taro plants in comparison to f. typica aphids which formed smaller colonies in significantly more time on banana plants. Reciprocal transfer of the two forms of P. nigronervosa aphids between their host plant species lowered performance on the transferred host plants. These results confirmed that P. nigronervosa f. typica from banana hosts and P. nigronervosa f. caladii from taro hosts are indeed two different species in relation to host plant utilization and suggested that the observed differences in their fitness characters represented distinct genotypes.

Understanding banana bunchy top disease epidemiology in Burundi for an enhanced and integrated management approach

“…In both study areas, susceptibility to the disease varied according to the genotype used, which is in agreement with reports from India and the Philippines (Thomas & Caruana, 2000; Geering, 2009). Moreover, Bhadra & Agarwala (2010) reported that under field conditions, the population of aphid vectors grows in response to the phenology of their respective host plants. Banana pseudostem colour influences aphid preference (Robson et al.…”

“…The aphid was initially reported to have occurred on member species of the Zingiberaceae and Araceae families, but morphological and morphometric studies confirmed that these aphids were in fact a separate species ( P. caladii ; Bhadra & Agarwala, 2010; Foottit et al. , 2010).…”

On the Morphological and Genotypic Variations of Two Congeneric species of Banana Aphid Pentalonia (Homoptera: Aphididae) from India

“…The two earlier considered genotypes or forms can thus be easily considered as two species P. nigronervosa and P. caladii on the basis of their morphological, b iological and electrophoretic variat ions. Between the two species of Pentalonia tested in this study, the typica species exp ressed lower fitness on banana host plant than the caladii species fro m taro host plant [18]. Such a difference in response to host plants is suggestive of strong genotype (aphids)-environment (host plants) interactions indicating increased genetic variat ion.…”

“…In a recent study based on morphological and molecu lar d ifferences, the two forms of the banana aphid were given their species status, respectively, [17]. Bhadra and Agarwala [18] further recorded ecological and bio logical differences between P. caladii and P. nigronervosa from Araceae and Musaceae plants, respectively and considered these as full species.…”

Host Races of the Cotton Aphid,Aphis gossypii, in Asexual Populations from Wild Plants of Taro and Brinjal

“…Molting of third and fourth instars was monitored, and molted skin was removed soon after the measurements were recorded. The time interval in hours from the final molt to the production of the first nymph by an apterous adult aphid was recorded as the D 1st PG (Bhadra and Agarwala 2010). …”