Asma Madad, SEE-U 2001 Prof. Tim Kittel, TA Erika Geiger Affects of Time of Day On Feeding Bouts of Butterfly Species on Lantana horrida and Lantana macropoda

Introduction: What are the effects of time of day on the average feeding bout of butterflies?  In terms of the actual study of the feeding behavior of individual butterflies and or species, the term feeding bout is applied to the observed feeding term for each individual.  Studies have shown that the chemical composition of plants often change with age, exposure to sunlight, or other environmental factors.  The Lantana is well known for its ability to attract butterflies, and studies have indicated that butterflies can recognize Lantana by sight.  Two species of Lantana are present within the Biosphere campus, namely L. macropoda and L. horrida.  Observations of the average feeding bouts of butterflies on examples of L. macropoda and L. horrida during different periods of the day will be conducted in order to deduce a possible relationship between average feeding bout duration and time of day, across different butterfly species.

Methods:  Three sites were selected for observation on the Biosphere campus that had substantial growth of either Lantana horrida or Lantana macropoda.  The sites were each examined for 15 minutes at three different times during the course of the day: approximately 6am, noon, and late afternoon for four consecutive days  Initial species and number of individuals was recorded, and was again recorded prior to the end of observation for each respective site. Individual butterflies were tracked for 1 minute utilizing a stop watch in order to gauge the approximate duration of feeding upon each flower head of the Lantana sp.  The amount of time spent on a single flower head was regarded as a single feeding event within the feeding bout of the individual . If the individual tracked left the area before the 1-minute interval, this was recorded, but the only important aspect for analysis was average feeding duration. Any other behavior exhibited within the 1-minute period such as circling, interactions between individuals and/or species, or rest periods was noted.  The data was analyzed with regards to the significance of time of day, site, plant (lantana macropoda or lantana horrida) and species in terms of average feeding bout in SPSS. The Kruskal-Wallis test and Mann- Whitney test were performed on the variables to determine the significance for average feeding bout.

Study Sites on Biosphere Campus

Site Descriptions: Site 1- Dry Lab Area: Large, unmaintained L. macropoda bush partly shaded under a large tree. Surrounded by paved walkways. Directly across form the large L. macropoda is an additional, smaller Lantana bush. Site 2 –Hotel Entrance: At front entrance to hotel, several smaller ornamental L. horrida are located on either side of front door, and in a decorative island surrounded by the driveway. There is a greater amount of coverage by the L. horrida on the left side of the entrance (approximately 5 bushes), and accordingly observations were focused on the left side. Site 3- Martin Education Building: Directly behind the building is an ornamental garden that contains approximately 7 L. horrida bushes, which are more substantial than those at the Hotel Entrance.

Apodemia mejicanus (Sonoran Metalmark) Danaus gilippus (Queen) Duskywing sp. Euptoieta claudia (Variegated Fritillary) Eurema nicippe (Sleepy Orange) Eurema proterpia (Tailed Orange) Hairstreak sp. Junonia coenia (Common Buckeye) Limenitis archippus (Viceroy) Metalmark sp. Papilio cresphontes (Giant Swallowtail) Papilio polyxenes (Black Swallowtail) Skipper sp. Sulphur sp. A Sulphur sp. B Zerene eurydice (California Dogface) Butterfly Species Observed at Sites

 Noticeable trends with regards to feeding activity at different times of the day and within certain representative species was graphed.  There appeared to be a noticeable increase in average feeding bout duration from early in the morning to late afternoon..  Based upon the Kruskal-Wallis and Mann- Whitney statistical tests it was determined that the time of day does not statistically affect average feeding bout of butterfly species (Kruskal-Wallis, P=.135).  Site does not significantly affect average feeding bout of butterfly species (Kruskal-Wallis, P=.622)  Lantana species does not significantly affect average feeding bout of butterfly species (Kruskal- Wallis, P=.344)  The only variable that was found to be significant with regards to the average feeding bout was the species tracked while feeding (Kruskal-Wallis, P=.008) Results: Figure 1: Average Feeding Bout for all Sites/Species (Early morning, Mid-day, Late afternoon)

Figure 1:Average Feeding Bout

Figure 2: Papilio Polyxenes

Figure 3: Hairstreak sp.

Figure 4: Duskywing sp.

Figure 5: Sulphur sp.

Discussion  The time of day, sites selected, and lantana species had no significant affect on the average feeding bout of the butterflies tracked.  Physiognamy could have affected the relative duration of the butterfly feeding bouts.  Many plant species have adapted to their specific pollinator type with certain features of nectar presentation.  Perhaps more conclusive evidence for butterfly feeding bouts could have been gathered with a comparison to other pollinators  Inaccuracies within the data may have arose in the tracking of individual butterflies, as many species remained on flower heads for less than 2 seconds at times. Time of day might not be significant due to variations in shaded portions of the plants at the respective sites. Without being able to mark individuals of the same species, accurate species and individual counts might be skewed. Larger species, such as the Black swallowtails were over represented within the species counts because of the ease with which it is to observe their foraging bouts. Intraspecific and interspecific competition was observed during the data collection, but was not included in the results

Conclusions Conclusions:  Based upon the results of this study, the null hypothesis was supported by the data collected.  The results of the Kruskal-Wallis and Mann-Whitney tests show that there is no significant difference in average feeding bout in terms of time of day, site and plant species for butterfly species.  For the species tracked, there was significance in terms of average feeding bout. These differences might be due to physiognomy, or competitive interference.  Time of day might not effect not effect the average feeding bout of butterflies due to the effects of natural variation within the sites that could affect feeding bouts  The daily feeding patterns of butterflies are important in the fulfillment of their role as long-distance pollinators, and in that respect, plant gene dispersal.

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