Effects of Vegetated Field Borders on Arthropods in Cotton Fields in Eastern North Carolina

The influence, if any, of 5m wide, feral, herbaceous field borders on pest and beneficial arthropods in commercial cotton, Gossypium hirsutum (L.) (Malvales: Malvaceae), fields was measured through a variety of sampling techniques over three years. In each year, 5 fields with managed, feral vegetation borders and five fields without such borders were examined. Sampling was stratified from the field border or edge in each field in an attempt to elucidate any edge effects that might have occurred. Early season thrips populations appeared to be unaffected by the presence of a border. Pitfall sampling disclosed no differences in ground-dwelling predaceous arthropods but did detect increased populations of crickets around fields with borders. Cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) populations were too low during the study to adequately assess border effects. Heliothines, Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), egg numbers and damage rates were largely unaffected by the presence or absence of a border, although in one instance egg numbers were significantly lower in fields with borders. Overall, foliage-dwelling predaceous arthropods were somewhat more abundant in fields with borders than in fields without borders. Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae) were significantly more abundant in fields with borders, but stink bugs, Acrosternum hilare (Say), and Euschistus servus (Say) (Hemiptera: Pentatomidae) numbers appeared to be largely unaffected by border treatment. Few taxa clearly exhibited distributional edge effects relative to the presence or absence of border vegetation. Field borders like those examined in this study likely will have little impact on insect pest management in cotton under current insect management regimens

Comovement and Investment Banking Networks Comovement and Investment Banking Networks

Abstract We test the hypothesis that investment banking networks affect stock prices and trading behavior. Consistent with the role of an investment bank as an information hub for segmented networks of investors, we find that stocks that share the same lead underwriter at their IPOs tend to move together. We also find that this comovement increases around a seasoned equity offering by the firm. Furthermore, firms that switch underwriters between their IPO and a subsequent SEO move less with the old-bank stocks and move more with the new-bank stocks after the switch even after controlling for potential endogeneity issues. The change in comovement is bigger for stocks completing their first SEO and for stocks with a larger change in ownership by institutions associated with the new bank. We thank Alex Butler, Yael Hochberg, Andy Puckett, Zheng Sun, and seminar participants at Rice University, the University of Wisconsin-Madison, the 2011 Western Finance Association meetings, and the 2011 Financial Management Association meetings for useful comments and suggestions. All remaining errors are our own. 1 Comovement and Investment Banking Networks Abstract We test the hypothesis that investment banking networks affect stock prices and trading behavior. Consistent with the role of an investment bank as an information hub for segmented networks of investors, we find that stocks that share the same lead underwriter at their IPOs tend to move together. We also find that this comovement increases around a seasoned equity offering by the firm. Furthermore, firms that switch underwriters between their IPO and a subsequent SEO move less with the old-bank stocks and move more with the new-bank stocks after the switch even after controlling for potential endogeneity issues. The change in comovement is bigger for stocks completing their first SEO and for stocks with a larger change in ownership by institutions associated with the new bank.

Comovement and Investment Banking Networks Comovement and Investment Banking Networks

Abstract We test the hypothesis that investment banking networks affect stock prices and trading behavior. Consistent with the role of an investment bank as an information hub for segmented networks of investors, we find that stocks that share the same lead underwriter at their IPOs tend to move together. We also find that this comovement increases around a seasoned equity offering by the firm. Furthermore, firms that switch underwriters between their IPO and a subsequent SEO move less with the old-bank stocks and move more with the new-bank stocks after the switch even after controlling for potential endogeneity issues. The change in comovement is bigger for stocks completing their first SEO and for stocks with a larger change in ownership by institutions associated with the new bank.