From the butterfly’s point of view: learned colour association determines differential pollination of two co-occurring mock verbains byAgraulis vanillae(Nymphalidae)

Abstract

Learning plays an important role in the location and utilization of nectar sources for pollinators. In this work we focus on the plant-pollinator interaction between the butterfly Agraulis vanillae (Nymphalidae) and two Glandularia plant species (Verbenaceae) that grow in sympatry. Bioassays using arrays of artificial flowers (red vs. lilac-purple) showed that naïve A. vanillae butterflies do not have innate colour preferences for any of the tested colours. Trained butterflies were able to learn to associate both floral colours with the presence of nectar rewards. Wild A. vanillae butterflies visited the red flowers of Glandularia peruviana much more frequently than the lilac-purple flowers of Glandularia venturii. Standing nectar crop measurements showed that G. peruviana flowers offered three times more sucrose than the flowers of G. venturii. Analyses confirmed that corolla colour of G. peruviana (red flowers) and G. venturii (lilac-purple flowers) were discriminable in the butterfly’s colour space. These findings may indicate flexibility in A. vanillae preferences due to a learned association between red coloration and higher nectar rewards.

Heliconiini butterflies can learn time-dependent reward associations

“…It is notable that some individuals do not pass the training criteria or learn the association. While this is consistent with other butterfly learning experiments [ 33 ], it would be interesting to investigate whether variation in body condition upon emergence or alternative foraging tactics anecdotally observed in wild Heliconius , such as stationary feeding from restricted plant clusters versus trap-line foraging from broad arrays of diverse plants [ 18 ] contribute to the variability observed in passing the training criterion. Regardless, our data indicate both Dryas and Heliconius can learn time-dependent associations.…”

True UV color vision in a butterfly with two UV opsins

“…The experiments and training took place indoors in a mesh enclosure constructed from PVC pipes, measuring 1 m × 75 cm × 75 cm, and the room temperature was 24° C. The top of the enclosure was lined with 8 fluorescent tubes (Philips TLD 965 18 W; Eindhoven, The Netherlands). Our apparatus for training and experiments was based on a design described in Zaccardi et al (2006) and previously used to test color vision in the monarch butterfly (Blackiston et al 2011; see also Swihart and Swihart 1970, Weiss and Papaj 2003, Takeuchi et al 2006, Rodrigues et al 2010, Kinoshita and Arikawa 2014, and Drewniak et al 2020 for other apparatus’ used in butterfly visual learning). It consists of two 3.0 cm diameter stimuli presented side-by-side, separated by 6 cm on two black platforms set on a larger black plate, measuring a total of 20 cm × 10 cm (see Figure 2 and Supporting Video 1).…”

Oviposition behaviour is not affected by ultraviolet light in a butterfly with sexually-dimorphic expression of a UV-sensitive opsin

“…The absence of UV reflectance in the hostplant and little-to-no stimulation of the UV photoreceptors suggests that UV discrimination does not directly affect Heliconius female oviposition. However, it is important to note that these conclusions are based on estimates of visual system stimulation which are inherently limited (Dell’Aglio et al ., 2018; Drewniak et al ., 2020; Finkbeiner & Briscoe, 2021), further highlighting the importance of our behavioural studies.…”