Behavioral ecologists might often benefit by the ability to directly measure an animal's body condition as estimate of foraging success, and ultimately fitness. Here we compare reliability effectiveness three indices that have been heavily used in morphometrics literature. We examined ratio index (body mass/body size), slope-adjusted (based on regression slopes generated from a reference population), residual (the residuals mass size). present results tests performed field laboratory two...

A large number of studies on both animals and humans have demonstrated that learning is influenced by context or secondary cues are present when an association formed. Few studies, however, examined the functional value attending to context. We first jumping spiders, Phidippus princeps, could be trained avoid aposematic, distasteful milkweed bugs, Oncopeltus fasciatus. Spiders readily attacked bugs exposure but were significantly less likely do so after eight trials, although they...

Salticid spiders are a tractable group for studies of learning. We presented Phidippus princeps Peckham & 1883 with the challenging task associating prey color cues in T-maze. Experimental were given opportunity to learn that cricket was hidden behind block particular color. To eliminate use other cues, we randomly assigned both position within maze, and maze location room. For control spiders, no predicted prey. gave two blocks trials. Each consisted four training trials followed by probe...

In species where the female mates more than once, sperm priority patterns have important implications for mating behavior of both sexes. The shape storage organs may play a role in determining patterns, although extent this effect has been controversial. Spiders provide an interesting test hypothesis because 2 phylogenetically distinct groups differ structure organs. entelegyne spiders, sperm-storage separate ducts entrance and exit. male inseminates through external fertilization duct....

The pholcid spider Holocnemus pluchei (Scopoli 1763) competes for food with conspecifics, and spiders reared on high levels are generally larger. In this study, we examined whether larger female body size (as estimated by tibia-patella length) translated into increased reproductive success in the form of clutch size, weight, average egg weight. Larger had more eggs thus heavier clutches, but there was no relationship between maternal We also looked a tradeoff weight number, found weak which...

Some species have sensory systems divided into subsystems with morphologically different sense organs that acquire types of information within the same modality. Jumping spiders (family Salticidae) eight eyes. Four eyes are directed anteriorly to view objects in front spider: a pair principal track targets their movable retinae, while immobile anterior lateral (AL) larger field and lower resolution. To test whether eyes, AL or both together mediate response looming stimuli, we presented...

Many predators exploit the chemical signatures of prey when foraging. We present a comparative study designed to test if foraging behavior Phidippus audax (Hentz 1845) is manipulated by substrate-borne chemicals left prey. Our findings suggest that P. do not use cues prey, while wolf spider Pardosa milvina 1844) in same experimental setup does respond cues. However, further examination into role on detection salticids required.

Species differ in whether they exhibit strong site fidelity or move readily among sites. To understand the adaptive significance of it is necessary to measure cost relocating new sites, but this very difficult with most species because entails following individuals during entire course their transition. We studied colonial web-building spider Metepeira incrassata (Araneae: Araneidae), which defends individual orb webs within a large, shared frame web. Colonies are heterogeneous habitats,...

Animals must selectively attend to relevant stimuli and avoid being distracted by unimportant stimuli. Jumping spiders (Salticidae) do this coordinating eyes with different capabilities. Objects are examined a pair of high-acuity principal eyes, whose narrow field view is compensated for retinal movements. The overlap in motion-sensitive anterior-lateral (ALEs), which direct their gaze new Using salticid-specific eyetracker, we monitored the direction as they primary stimulus. We then...