Spurius

Abstract: In the beginning, Rome was ruled by kings. Their expulsion heralded the foundation of the Republic, a political system strong enough to withstand both internal and external threats to the state. Among these internal threats was the possibility of an elite man trying to set himself up as a king. Modern scholarship agrees that there were three such attempts to recreate a monarchy in the early Republic: Spurius Cassius in 485, Spurius Maelius in 439 and Marcus Manlius Capitolinus in 385/4. The affectatores regni purposefully courted the plebs in order to gain supreme power. But Roman virtue was too strong; all three men were caught, tried (either publicly or privately) and executed. Their possessions were seized and consecrated to the gods; their families shunned their memory. These attempts to establish tyranny revealed both the fragility and the power of the Republic.

Abstract: Birdsong has important functions in attracting and competing for mates, and song characteristics are thought to diverge rapidly during the process of speciation. In contrast, other avian vocalizations that may have non-reproductive functions, such as calls, are thought to be more evolutionarily conserved and may diverge more slowly among taxa. This study examines differences in both male song and an acoustically simpler vocalization, the ‘jeet’ call, between two closely related taxa, Icterus spurius and I. fuertesi. A previous study comparing song syllable type sharing within and between I. spurius and I. fuertesi indicated that their songs do not differ discernibly. Here we measured 18 acoustic characteristics of their songs and found strong evidence supporting this prior finding. In contrast, we measured 17 acoustic characteristics of jeet calls and found evidence of significant divergence between the two taxa in many of these characteristics. Calls in I. fuertesi have a longer duration, a larger frequency bandwidth, a lower minimum frequency, a lower beginning frequency, and greater levels of both frequency and amplitude modulation in comparison to the calls of I. spurius. In addition, I. fuertesi calls contain two distinct parts, while the calls of I. spurius have only one part. Thus, we find evidence of divergence in the calls of the two taxa but not their songs challenging the widespread assumption that complex bird song evolves more rapidly than other types of vocalizations. Understanding divergence in multiple vocalization types as well as other behavioral, morphological, and molecular traits is important to understanding the earliest stages of speciation.