Moths as potential pollinators in avocado (Persea americana) orchards in temperate regions

Abstract

Avocado (Persea americana) flowers are primarily diurnal, however low minimum overnight temperatures can delay in the opening of female-phase flowers such that the flowers open late in the day and remain open overnight. To determine whether moths are important visitors to avocado flowers at night, we trapped moths in the Bay of Plenty, New Zealand, and examined the pollen moths carried. 11.5% of moths carried avocado pollen grains, and 50.4% of all moths were found to carry pollen grains from other plant species. Moth species diversity was highly variable between orchards, but Ichneutica mutans, Ichneutica ustistriga, Epyaxa rosearia, Rhapsa scotosialis, Phrissogonus laticostatus were observed at all sites and Ichneutica steropastis at three sites, with avocado pollen grains found on 10%-33% of these individual species. We suggest that these species may be the most important pollinating moth species because of their abundance, proportion of individuals carrying avocado pollen, and the number of pollen grains per individual. This exploratory study has shown that moths are capable of carrying avocado pollen grains and may be providing a background pollination service to complement that of honey bees (Apis mellifera). To better understand moth contribution to pollination, fruit set needs to be assessed.

Moths complement bumblebee pollination of red clover: a case for day-and-night insect surveillance

“…Clearly camera surveillance can provide a temporally representative view of flower visitation [ 27 ], which is difficult to achieve through visual observations [ 15 ]. Pollen microscopy and DNA metabarcoding reveal the types of pollen carried by nocturnal insects [ 14 , 16 , 25 ], while exclusion experiments establish which agricultural plants depend on nocturnal pollination [ 13 ]. However, the scale of nocturnal pollination has proven particularly difficult to quantify [ 17 ], and cameras can provide robust estimates of relative visitation by day- and night-active pollinators [ 32 ].…”

“…moths, are particularly poorly understood, despite facing additional threats from artificial light at night [9][10][11][12]. Evidence is mounting on the agricultural and economic importance of nocturnal pollination, and recent studies showing how apples [13] and avocados [14] benefit from flower visits at night. Still, it remains difficult to generate rigorous, like-for-like comparisons between dayand night-time pollinators [15,16] and too little is known about the scale of nocturnal pollination [17].…”

A global review demonstrating the importance of nocturnal pollinators for crop plants

“…Some examples of these are: bumble bees ( Bombus spp. ; Cutting et al, 2018; McBrydie et al, 2017), solitary bees (Broussard et al, 2011), and non‐bee taxa such as butterflies (Rasheed et al, 2015), flies (Cook et al, 2020; Howlett & Gee, 2019; Stavert et al, 2018) and moths (Buxton et al, 2021; Manning & Cutler, 2013; Pattemore et al, 2018), yet all of these insect groups are still understudied compared with honey bees (Rader et al, 2016). Other understudied pollinators include vertebrates such as birds, lizards and mammals.…”

“…Cutler et al, 2012); thus their contribution to the pollination of crop or medicinally important plants remains largely unknown and may be under‐represented in the literature (Buxton et al, 2018; Macgregor & Scott‐Brown, 2020). There is, however, a growing appreciation that nocturnal insects (particularly moths) may be contributing substantially to the pollination of commercially important crops such as apples (Robertson et al, 2021), avocado (Buxton et al, 2021), and gourds (Lu et al, 2021) making this area of research very timely.…”

Bee and non-bee pollinator importance for local food security

“…Thus, CropPol potentially underestimates the contribution of nocturnal pollination. For instance, this global database does not record nocturnal pollination of apple and cucurbits; however, recent exclusion experiments showed that the contribution of nocturnal pollinators to pollination is significant [28][29][30].…”