Light environments affect herbivory patterns but not reproductive performance of a multivoltine specialist moth, Pareuchaetes pseudoinsulata

Unravelling the responses of insect herbivores to light-environment-mediated variation in the traits of their host plants is central to our understanding of the nutritional ecology of, and factors driving the population dynamics in, these species. This study examined the effect of light environment (shaded vs full-sun habitat) on leaf toughness and leaf nutritional quality in Chromolaena odorata (an invasive species in West Africa) and related these attributes to the abundance, herbivory patterns and reproductive performance of a multivoltine specialist moth, Pareuchaetes pseudoinsulata (a biological control agent). In this system, plants growing in shaded areas in the field experienced more herbivory and had higher herbivore abundance than those growing in full-sun. In the laboratory, P. pseudoinsulata larvae consumed significantly greater amounts of shaded foliage relative to full-sun foliage. However, reproductive performance metrics such as mating success, pre-oviposition period, number of eggs laid, duration of egg laying, egg hatchability, and adult longevity in P. pseudoinsulata did not differ according to foliage types. Reduced leaf toughness, increased water and nitrogen contents in shaded leaves coincided with increased leaf consumption by the larvae of P. pseudoinsulata. In summary, this study showed for the first time that light environments affect herbivory patterns but not reproductive performance of P. pseudoinsulata and hypothesized that high foliar nitrogen and water contents in shaded leaves resulted in feedback and necessity consumption patterns.

Reoccurrence of Pareuchaetes pseudoinsulata Rego Barros (Arctiidae: Lepidoptera) population in Thiruvananthapuram district of Kerala, India: A biological control agent of the weed, Chromolaena odorata (Asteraceae)

Authors report the reoccurrence of <em>Pareuchaetes pseudoinsulata</em> Rego Barros larvae at Technopark campus, Thiruvananthapuram. The larvae of<em> P. pseudoinsulata</em> were found feeding voraciously on terminal and axillary buds and leaves of <em>Chromolena odorata</em>. The recent report helps to identify the elite and resistant population for further field release to control <em>C. odorata</em>.

Intrusion of devil weed Chromolaena odorata, an exotic invasive, into Kinnerasani and Eturnagaram wildlife sanctuaries, Telangana, India

The spread of devil weed is alarming in areas of <em>podu</em> cultivation, on the bunds of agricultural lands, wastelands, along roadsides, tracks, forest gaps, protected areas and plantations in the two said wildlife sanctuaries. It is found invading new territories easily along the river banks and steadily destroying the riparian elements. The manual removal of this weed (mechanical method) before flowering is the effective means to mitigate the spread of the species in comparison to the biological (<em>Pareuchaetes pseudoinsulata, P. insulata, Actinote thalia-pyrrha</em>) and chemical (Glyphosate, Triclopyrester) methods attempted. It is not trouble in its native habitat but is weedy in India for want of natural enemies to keep it under control. It is a mandate to prevent the loss of native biodiversity due to biological invasions. Conversely, there is an urgent need to devise action plans by managers of the respective wildlife sanctuaries to control and eradicate it. The local people are to be educated of its potential dangers to their farming on one hand and NTFP extraction from the local forests on the other. The Government of India has to develop a national level policy towards the control of invasive alien weeds in general and implement it at the earliest before we loose our indigenous biodiversity once for all.

The biology and host specificity of Pareuchaetes aurata aurata (Lepidoptera: Arctiidae), a ‘new association’ biological control agent for Chromolaena odorata (Compositae)

Pareuchaetes aurata aurata (Butler) from Chromolaena jujuensis in northern Argentina was tested as a biological control candidate for the composite weed C. odorata. The larvae feed voraciously and complete their development on C. odorata. The host-plant feeding range of P. a. aurata is limited to the genus Chromolaena. It is suggested that the egg-laying behaviour of P. a. aurata, which scatters its eggs around the base of the host-plant, will help to overcome the problem of ant predation which prevented the establishment of Pareuchaetes pseudoinsulata Rego Barros, which lays its eggs in batches, in South Africa. Any possible benefits of the new association between P. a. aurata and C. odorata may also contribute to the success of this biological control programme.