A Systematic Review on Opuntia (Cactaceae; Opuntioideae) Flower-Visiting Insects in the World with Emphasis on Mexico: Implications for Biodiversity Conservation

Opuntia spp. are cacti with high ecological, economic and conservation interest in semiarid environments, particularly in Mexico. We conducted a systematic search of the existing peer-reviewed literature about the state of knowledge of pollination ecology on these plants. We documented the most studied Opuntia species worldwide with an emphasis on Mexico. We found that only 15% of Opuntia species described have been investigated so far, and studies were mainly focused on comprehension of the biology of a single species. Despite the economic and cultural importance of Opuntia, there is a significant lack of knowledge about the flower-visiting insects and their taxonomic identity. We provide a checklist of the insect species associated with Opuntia spp. Through a circular network, we visualize the complex Opuntia flower-visiting insect relationship, and we detected a set of key species constituting the generalist core of the networks constructed. Since pollination is crucial for crop production, a better understanding of ecological interactions would inform management measures to strengthen biodiversity and agriculture sustainability as well as productivity in arid and marginal lands. Further research on pollination ecology is needed to improve the conservation status of the insects associated with Opuntia species.

Agave and Opuntia Species as Sustainable Feedstocks for Bioenergy and Byproducts

Currently, Mexico is facing an energy transition, therefore updated policy regulations pertaining to the sustainable use of biomass are needed. In particular, policy that favors the sustainable use of biomass to produce energy and bioproducts to privilege climate change mitigation is needed. This review describes the use of maguey (Agave spp.) and nopal (Opuntia spp.; also known as “cactus”) for biofuel production, especially in marginal areas. Emphasis is given on documented case studies discussing features of production and cultivation for both maguey and nopal, in addition to their potential for fuel production. Environmental and social sustainability issues in terms of waste value and new opportunities as bioenergy feedstocks and byproducts are also discussed. Although the paper does not deeply describe aspects of biomass transformation, such as bioprocess configurations, it gives characteristics of production in addition to cultivation. Agave and Opuntia species may represent a suitable feedstock for biofuels, bioproducts, bioenergy and biorefineries, especially in dry lands (semi-arid and dry sub-humid), deforested areas, agroforestry systems and agricultural semi-terraces known as metepantle in Mexico.

Two new species of nopal (Opuntia, Cactaceae) from the Baja California Peninsula (Mexico)

Two new species of prickly-pear/nopal (Opuntia sierralagunensis and O. caboensis, Cactaceae) are described and illustrated here; both occur in the tropical deciduous forest plant community found in the Cape region of the Baja California Peninsula, Mexico. Previously, these two species had been overlooked and were considered extreme forms of species described from the Sierra de La Giganta (e.g., O. comonduensis, O tapona), located hundreds of kilometers away. However, with an improved collection of specimens and field knowledge of the Opuntia species in the region, we have determined that these prickly-pears are new to science and are restricted to the Cape region. We provide justification to separate them from sympatric congeners and other similar species in the southern peninsula.

Evaluation of the cytotoxic and antiviral effects of ethanol extract of three Opuntia species of Peste des Petits ruminant virus

Purpose: To assess in vitro the virocidal effects of different species of cactus plant on the lethal action of Peste des petits virus (PPRV).Method: Ethanol extracts of different cactus plants were obtained. A serial twofold dilution of the extracts was prepared. Cytotoxic and antiviral activities were examined through MTT assay at various concentrations. Vero cell lines were grown in 96 well plates up to an 80 % confluent monolayer. The plates were divided into two groups, one for antiviral and the other for cytotoxicity activity. The cells were exposed to various concentrations of the ethanol extracts to assess the cytotoxicity, whereas to assess the antiviral activity, PPRV was re-incubated with the extracts and then exposed to cells. MMT dye was added and the results were evaluated as cell survival (%).Results: At higher concentrations, i.e., 500 - 1000 μg/mL, ethanol extracts from all the Opuntia species displayed cytotoxic effects. The ethanol extract of OM exhibited the greatest antiviral potential of all the extracts, while the extract of Opuntia stricta (OS) was the least effective against PPRV in the cultured cells. There were significant differences (p < 0.05) in the concentration of Opuntia manocantha (OM), Opuntia delinii OD and Opuntia stricta (OS) with reference to antiviral activity. OM showed antiviral activity against PPRV from 3.25 to 125 μg/mL, OD antiviral activity from 31.25 to 62.5 ug/ml whereas OS showed antiviral activity at 2.5 μg/mLConclusion: The ethanol extract of Opuntia species reduces the infection of PPRV in Caprine. Keywords: Cactus, Opuntia spp., Peste des petits ruminants virus (PPRV), Vero cell line